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PGND

DAP

GATE

COMP

VIN

CSH

RCT

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LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

LM3429/-Q1 N-Channel Controller for Constant Current LED Drivers

1 Features 3 Description

The LM3429 is a versatile high voltage N-channel

1• LM3429-Q1 is AEC-Q100 Grade 1 Qualified for MosFET controller for LED drivers. It can be easily

Automotive Applications configured in buck, boost, buck-boost and SEPIC

• VIN Range From 4.5 V to 75 V topologies. This flexibility, along with an input voltage

• Adjustable Current Sense Voltage rating of 75V, makes the LM3429 ideal for

illuminating LEDs in a very diverse, large family of

• High-Side Current Sensing applications.

• 2-Ω, 1-A Peak MosFET Gate Driver Adjustable high-side current sense voltage allows for

• Input Undervoltage Protection tight regulation of the LED current with the highest

• Overvoltage Protection efficiency possible. The LM3429 uses Predictive Off-

• PWM Dimming time (PRO) control, which is a combination of peak

current-mode control and a predictive off-timer. This

• Analog Dimming method of control eases the design of loop

• Cycle-by-Cycle Current Limit compensation while providing inherent input voltage

• Programmable Switching Frequency feed-forward compensation.

• Low Profile 14-lead HTSSOP Package The LM3429 includes a high-voltage startup regulator

• Thermal Shutdown that operates over a wide input range of 4.5 V to 75

V. The internal PWM controller is designed for

2 Applications adjustable switching frequencies of up to 2 MHz, thus

enabling compact solutions. Additional features

• LED Drivers - Buck, Boost, Buck-Boost, SEPIC include analog dimming, PWM dimming, overvoltage

• Indoor and Outdoor SSL protection, undervoltage lock-out, cycle-by-cycle

current limit, and thermal shutdown.

• Automotive

• General Illumination Device Information(1)

• Constant-Current Regulators PART NUMBER PACKAGE BODY SIZE (NOM)

LM3429 HTSSOP (14) 5.00 mm × 4.40 mm

LM3429-Q1

(1) For all available packages, see the orderable addendum at

the end of the data sheet.

Typical Boost Application Circuit

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Table of Contents

1 Features.................................................................. 18 Application and Implementation ........................ 22

8.1 Application Information............................................ 22

2 Applications ........................................................... 18.2 Typical Applications ................................................ 24

3 Description............................................................. 19 Power Supply Recommendations...................... 53

4 Revision History..................................................... 29.1 Input Supply Current Limit ...................................... 53

5 Pin Configuration and Functions......................... 310 Layout................................................................... 53

6 Specifications......................................................... 410.1 Layout Guidelines ................................................. 53

6.1 Absolute Maximum Ratings ...................................... 410.2 Layout Example .................................................... 54

6.2 ESD Ratings.............................................................. 411 Device and Documentation Support................. 55

6.3 Recommended Operating Conditions....................... 411.1 Device Support...................................................... 55

6.4 Thermal Information.................................................. 511.2 Documentation Support ........................................ 55

6.5 Electrical Characteristics .......................................... 511.3 Related Links ........................................................ 55

6.6 Typical Characteristics ............................................. 711.4 Community Resources.......................................... 55

7 Detailed Description.............................................. 911.5 Trademarks........................................................... 55

7.1 Overview................................................................... 911.6 Electrostatic Discharge Caution............................ 56

7.2 Functional Block Diagram......................................... 911.7 Glossary................................................................ 56

7.3 Feature Description................................................. 10 12 Mechanical, Packaging, and Orderable

7.4 Device Functional Modes........................................ 21 Information ........................................................... 56

4 Revision History

NOTE: Page numbers for previous revisions may differ from page numbers in the current version.

Changes from Revision G (April 2013) to Revision H Page

• Added Pin Configuration and Functions section, Handling Rating table, Feature Description section, Device

Functional Modes,Application and Implementation section, Power Supply Recommendations section, Layout

section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information

section ................................................................................................................................................................................... 1

Changes from Revision F (May 2013) to Revision G Page

• Changed layout of National Data Sheet to TI format ........................................................................................................... 51

• Changed layout of National Data Sheet to TI format ........................................................................................................... 52

Product Folder Links: LM3429 LM3429-Q1

VIN

nDIM

AGND

OVP

CSH

RCT

GATE

COMP HSP

DAP

8NC

PGND

HSN

VCC

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

5 Pin Configuration and Functions

PWP Package

14- Pin HTSSOP

Top View

Pin Functions

PIN I/O DESCRIPTION APPLICATION INFORMATION

NO. NAME

Bypass with 100 nF capacitor to AGND as close to the device as

1 VIN I Input Voltage possible in the circuit board layout.

2 COMP I Compensation Connect a capacitor to AGND to set compensation.

Connect a resistor to AGND to set signal current. For analog

3 CSH I Current Sense High dimming, connect current source or potentiometer to AGND (see

Analog Dimming section).

Connect a resistor from the switch node and a capacitor to AGND to

4 RCT I Resistor Capacitor Timing set the switching frequency.

Connect to PGND through the DAP copper circuit board pad to

5 AGND GND Analog Ground provide proper ground return for CSH, COMP, and RCT.

Connect to a resistor divider from the output (VO) or the input to

program output overvoltage lockout (OVLO). Turn-off threshold is

6 OVP I Overvoltage Protection 1.24 V and hysteresis for turn-on is provided by 20 µA current

source.

Connect a PWM signal for dimming as detailed in the PWM Dimming

section and/or a resistor divider from VIN to program input

7 nDIM I Not DIM input undervoltage lockout (UVLO). Turn-on threshold is 1.24 V and

hysteresis for turn-off is provided by 20 µA current source.

8 NC No Connection Leave open.

Connect to AGND through DAP copper pad to provide ground return

9 PGND GND Power Ground for GATE.

10 GATE O Gate Drive Output Connect to the gate of the external NFET.

11 VCC I Internal Regulator Output Bypass with a 2.2 µF–3.3 µF, ceramic capacitor to PGND.

Connect to the drain of the main N-channel MosFET switch for RDS-

12 IS I Main Switch Current Sense ON sensing or to a sense resistor installed in the source of the same

device.

Connect through a series resistor to LED current sense resistor

13 HSP I LED Current Sense Positive (positive).

Connect through a series resistor to LED current sense resistor

14 HSN I LED Current Sense Negative (negative).

DAP DAP GND Thermal pad on bottom of IC Connect to AGND and PGND.

(15)

Product Folder Links: LM3429 LM3429-Q1

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

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6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1)(2)

MIN MAX UNIT

VIN, nDIM –0.3 76

OVP, HSP, HSN –0.3 76

RCT –0.3 3

–0.3 76

IS –2 for 100 ns V

Voltage VCC –0.3 8

COMP, CSH –0.3 6

–0.3 VCC

GATE –2.5 for 100 ns VCC+2.5 for 100 ns

–0.3 0.3

PGND –2.5 2.5 for 100 ns

VIN, nDIM –1 mA

OVP, HSP, HSN –100 µA

RCT –1 5

Continuous Current mA

IS –1

COMP, CSH –200 200 µA

GATE –1 1 mA

Maximum Junction Temperature Internally Limited

Maximum Lead Temperature (Reflow and Solder) (3) 260 °C

Continuous Power Dissipation Internally Limited

Storage Temperature, Tstg –65 150 °C

(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings

only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended

Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

(2) If Military/Aerospace specified devices are required, contact the Texas Instruments Sales Office/Distributors for availability and

specifications.

(3) Refer to http://www.ti.com/packaging for more detailed information and mounting techniques.

6.2 ESD Ratings VALUE UNIT

LM3429 IN PWP PACKAGE

Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins(1) ±2000

V(ESD) Electrostatic discharge V

Charged device model (CDM), per JEDEC specification JESD22-C101, all ±1000

pins(2)

LM3429-Q1 IN PWP PACKAGE

Human body model (HBM), per AEC Q100-002(3) ±2000

V(ESD) Electrostatic discharge V

Charged device model (CDM), per AEC Q100-011 ±1000

(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.

(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

(3) AEC Q100-002 indicates HBM stressing is done in accordance with the ANSI/ESDA/JEDEC JS-001 specification.

6.3 Recommended Operating Conditions MIN MAX UNIT

Operating Junction Temperature Range –40 125 °C

Input Voltage VIN 4.5 75 V

Product Folder Links: LM3429 LM3429-Q1

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LM3429-Q1

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SNVS616H –APRIL 2009–REVISED JULY 2015

6.4 Thermal Information LM3429-Q1 LM3429

THERMAL METRIC(1) PWP (HTSSOP) PWP (HTSSOP) UNIT

14 PINS 14 PINS

RθJA Junction-to-ambient thermal resistance 47.8 47.8 °C/W

RθJC(top) Junction-to-case (top) thermal resistance 26.5 26.5 °C/W

RθJB Junction-to-board thermal resistance 22.3 22.3 °C/W

ψJT Junction-to-top characterization parameter 0.7 0.7 °C/W

ψJB Junction-to-board characterization parameter 22.1 22.1 °C/W

RθJC(bot) Junction-to-case (bottom) thermal resistance 3.3 3.3 °C/W

(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application

report, SPRA953.

6.5 Electrical Characteristics

MIN and MAX limits apply TJ= (−40°C to 125°C) unless specified otherwise. Unless otherwise stated the following condition

applies: VIN = 14 V.

PARAMETER TEST CONDITIONS MIN(1) TYP(2) MAX(1) UNIT

STARTUP REGULATOR (VCC)

VCC-REG VCC Regulation ICC = 0 mA 6.3 6.9 7.35 V

ICC-LIM VCC Current Limit VCC = 0V 20 27 mA

IQQuiescent Current Static 1.6 3

VCC-UVLO VCC UVLO Threshold VCC Increasing 4.17 4.5

VCC Decreasing 3.7 4.08 V

VCC-HYS VCC UVLO Hysteresis 0.1

OVERVOLTAGE PROTECTION (OVP)

VTH-OVP OVP OVLO Threshold OVP Increasing 1.18 1.24 1.28 V

IHYS-OVP OVP Hysteresis Source Current OVP Active (high) 10 20 30 µA

ERROR AMPLIFIER

VCSH CSH Reference Voltage With Respect to AGND 1.21 1.235 1.26 V

Error Amplifier Input Bias Current MIN, MAX: TJ= 25°C –0.6 0 0.6 µA

COMP Sink / Source Current 10 26 40

Transconductance 100 µA/V

Linear Input Range (3) ±125 mV

Transconductance Bandwidth -6dB Unloaded

Response(3), MIN: TJ= 0.5 1 MHz

25°C

OFF TIMER (RCT)

tOFF-MIN Minimum Off-time RCT = 1V through 1 kΩ35 75 ns

RRCT RCT Reset Pulldown Resistance 36 120 Ω

VRCT VIN/25 Reference Voltage VIN = 14V 540 565 585 mV

PWM COMPARATOR

COMP to PWM Offset 700 800 900 mV

CURRENT LIMIT (IS)

VLIM Current Limit Threshold 215 245 275 mV

VLIM Delay to Output 35 75 ns

tON-MIN Leading Edge Blanking Time 75 250 450

(1) All limits specified at room temperature (TYP) and at temperature extremes (MIN/MAX). All room temperature limits are 100%

production tested. All limits at temperature extremes are specified through correlation using standard Statistical Quality Control (SQC)

methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).

(2) Typical numbers are at 25°C and represent the most likely norm.

(3) These electrical parameters are specified by design, and are not verified by test.

Product Folder Links: LM3429 LM3429-Q1

LM3429

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SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Electrical Characteristics (continued)

MIN and MAX limits apply TJ= (−40°C to 125°C) unless specified otherwise. Unless otherwise stated the following condition

applies: VIN = 14 V.

PARAMETER TEST CONDITIONS MIN(1) TYP(2) MAX(1) UNIT

HIGH SIDE TRANSCONDUCTANCE AMPLIFIER

Input Bias Current 10 µA

Transconductance 20 119 mA/V

Input Offset Current –1.5 0 1.5 µA

Input Offset Voltage –7 0 7 mV

Transconductance Bandwidth ICSH = 100 µA(3), MIN: TJ250 500 kHz

= 25°C

GATE DRIVER (GATE)

RSRC(GATE) GATE Sourcing Resistance GATE = High 2 6 Ω

RSNK(GATE) GATE Sinking Resistance GATE = Low 1.3 4.5

UNDERVOLTAGE LOCKOUT and DIM INPUT (nDIM)

VTH-nDIM nDIM / UVLO Threshold 1.18 1.24 1.28 V

IHYS-nDIM nDIM Hysteresis Current 10 20 30 µA

THERMAL SHUTDOWN

TSD Thermal Shutdown Threshold (3) 165 °C

THYS Thermal Shutdown Hysteresis (3) 25

Product Folder Links: LM3429 LM3429-Q1

DUTY CYCLE (%)

ILED (A)

1.0

0.8

0.6

0.4

0.2

0.00 20 40 60 80 100

100 Hz

500 Hz

ICSH (éA)

ILED (A)

1.0

0.8

0.6

0.4

0.2

0.0 0 20 40 60 80 100

VIN (V)

ILED (A)

1.00

0.99

0.98

0.97

0.96 5 10 15 20 25 30

VIN (V)

ILED (A)

1.05

1.03

1.01

0.99

0.97 0 16 32 48 64 80

VIN (V)

EFFICIENCY (%)

100

80 10 15 20 25 30

VIN (V)

EFFICIENCY (%)

100

70 0 16 32 48 64 80

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

6.6 Typical Characteristics

TA= 25°C and VIN = 14 V unless otherwise specified. The measurements for Figure 1 and Figure 3 were made using the

standard boost evaluation board from AN-1986 (SNVA404). The measurements for Figure 2,Figure 4, and Figure 5,Figure 6

were made using the standard buck-boost evaluation board from AN-1985 (SNVA403).

Figure 2. Buck-Boost Efficiency vs Input Voltage

Figure 1. Boost Efficiency vs Input Voltage VO= 20 V (6 LEDs)

VO= 32 V (9 LEDs)

Figure 3. Boost LED Current vs Input Voltage Figure 4. Buck-boost LED Current vs Input Voltage

VO= 32 V (9 LEDs) VO= 20 V (6 LEDs)

Figure 5. Analog Dimming Figure 6. PWM Dimming

VO= 20 V (6 LEDs) VO= 20V (6 LEDs)

Product Folder Links: LM3429 LM3429-Q1

TEMPERATURE (°C)

tON-MIN (ns)

280

275

270

265

260

255

250-50 -14 22 58 94 130

TEMPERATURE (°C)

VRCT (mV)

569

568

567

566

565

564-50 -14 22 58 94 130

TEMPERATURE (°C)

VLIM (mV)

246

244

242

240

238-50 -14 22 58 94 130

TEMPERATURE (°C)

VCSH (V)

1.250

1.245

1.240

1.235

1.230

1.225

1.220-50 -14 22 58 94 130

TEMPERATURE (°C)

VCC (V)

7.10

7.05

7.00

6.95

6.90

6.85

6.80-50 -14 22 58 94 130

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Typical Characteristics (continued)

TA= 25°C and VIN = 14 V unless otherwise specified. The measurements for Figure 1 and Figure 3 were made using the

standard boost evaluation board from AN-1986 (SNVA404). The measurements for Figure 2,Figure 4, and Figure 5,Figure 6

were made using the standard buck-boost evaluation board from AN-1985 (SNVA403).

Figure 7. VCSH vs. Junction Temperature Figure 8. VCC vs. Junction Temperature

Figure 10. VLIM vs. Junction Temperature

Figure 9. VRCT vs. Junction Temperature

Figure 11. tON-MIN vs. Junction Temperature

Product Folder Links: LM3429 LM3429-Q1

PWM

Start new on time

nDIM

UVLO

HYSTERESIS

COMP

REFERENCE

CURRENT

LIMIT

CSH

HSN

LOGIC

HSP

UVLO

GATE

PGND

VccUVLO

Thermal

Limit

TLIM

VIN/25

Standby

Dimming

Reset

Dominant

RCT

LEB

AGND

VCC

VIN

6.9V LDO

Regulator

OVP

HYSTERESIS

20 PA

1.24V

800 mV

1.24V

20 PA

1.24V

245 mV

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

7 Detailed Description

7.1 Overview

The LM3429 is an N-channel MosFET (NFET) controller for buck, boost and buck-boost current regulators which

are ideal for driving LED loads. The controller has wide input voltage range allowing for regulation of a variety of

LED loads. The high-side differential current sense, with low adjustable threshold voltage, provides an excellent

method for regulating output current while maintaining high system efficiency. The LM3429 uses a Predictive Off-

time (PRO) control architecture that allows the regulator to be operated using minimal external control loop

compensation, while providing an inherent cycle-by-cycle current limit. The adjustable current sense threshold

provides the capability to amplitude (analog) dim the LED current and the output enable/disable function allows

for PWM dimming using no external components. When designing, the maximum attainable LED current is not

internally limited because the LM3429 is a controller. Instead it is a function of the system operating point,

component choices, and switching frequency allowing the LM3429 to easily provide constant currents up to 5A.

This simple controller contains all the features necessary to implement a high-efficiency versatile LED driver.

7.2 Functional Block Diagram

Product Folder Links: LM3429 LM3429-Q1

D=INO VV +

D= INO VV -

D= O

iL (t)

ÂiL-PP

IL-MAX

IL-MIN

tON = DTStOFF = (1-D)TS

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

7.3 Feature Description

7.3.1 Current Regulators

Current regulators can be designed to accomplish three basic functions: buck, boost, and buck-boost. All three

topologies in their most basic form contain a main switching MosFET, a recirculating diode, an inductor and

capacitors. The LM3429 is designed to drive a ground referenced NFET which is perfect for a standard boost

regulator. Buck and buck-boost regulators, on the other hand, usually have a high-side switch. When driving an

LED load, a ground referenced load is often not necessary, therefore a ground referenced switch can be used to

drive a floating load instead. The LM3429 can then be used to drive all three basic topologies as shown in the

Typical Applications section.

Looking at the buck-boost design, the basic operation of a current regulator can be analyzed. During the time

that the NFET (Q1) is turned on (tON), the input voltage source stores energy in the inductor (L1) while the output

capacitor (CO) provides energy to the LED load. When Q1 is turned off (tOFF), the re-circulating diode (D1)

becomes forward biased and L1 provides energy to both COand the LED load. Figure 12 shows the inductor

current (iL(t)) waveform for a regulator operating in CCM.

Figure 12. Ideal CCM Regulator Inductor Current iL(t)

The average output LED current (ILED) is proportional to the average inductor current (IL) , therefore if ILis tightly

controlled, ILED will be well regulated. As the system changes input voltage or output voltage, the ideal duty cycle

(D) is varied to regulate ILand ultimately ILED. For any current regulator, D is a function of the conversion ratio:

Buck

(1)

Boost

(2)

Buck-Boost

(3)

7.3.2 Predictive Off-Time (PRO) Control

PRO control is used by the LM3429 to control ILED. It is a combination of average peak current control and a one-

shot off-timer that varies with input voltage. The LM3429 uses peak current control to regulate the average LED

current through an array of HBLEDs. This method of control uses a series resistor in the LED path to sense LED

current and can use either a series resistor in the MosFET path or the MosFET RDS-ON for both cycle-by-cycle

current limit and input voltage feed forward. D is indirectly controlled by changes in both tOFF and tON, which vary

depending on the operating point.

Product Folder Links: LM3429 LM3429-Q1

VSW

LM3429

RCT

Start tON

VIN/25

Reset timer

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

Feature Description (continued)

Even though the off-time control is quasi-hysteretic, the input voltage proportionality in the off-timer creates an

essentially constant switching frequency over the entire operating range for boost and buck-boost topologies.

The buck topology can be designed to give constant ripple over either input voltage or output voltage, however

switching frequency is only constant at a specific operating point .

This type of control minimizes the control loop compensation necessary in many switching regulators, simplifying

the design process. The averaging mechanism in the peak detection control loop provides extremely accurate

LED current regulation over the entire operating range.

PRO control was designed to mitigate “current mode instability” (also called “sub-harmonic oscillation”) found in

standard peak current mode control when operating near or above 50% duty cycles. When using standard peak

current mode control with a fixed switching frequency, this condition is present, regardless of the topology.

However, using a constant off-time approach, current mode instability cannot occur, enabling easier design and

control.

Predictive off-time advantages:

• There is no current mode instability at any duty cycle.

• Higher duty cycles / voltage transformation ratios are possible, especially in the boost regulator.

The only disadvantage is that synchronization to an external reference frequency is generally not available.

7.3.3 Switching Frequency

An external resistor (RT) connected between the RCT pin and the switch node (where D1, Q1, and L1 connect),

in combination with a capacitor (CT) between the RCT and AGND pins, sets the off-time (tOFF) as shown in

Figure 13. For boost and buck-boost topologies, the VIN proportionality ensures a virtually constant switching

frequency (fSW).

Figure 13. Off-timer Circuitry for Boost and Buck-boost Regulators

For a buck topology, RTand CTare also used to set tOFF, however the VIN proportionality will not ensure a

constant switching frequency. Instead, constant ripple operation can be achieved. Changing the connection of RT

in Figure 13 from VSW to VIN will provide a constant ripple over varying VIN. Adding a PNP transistor as shown in

Figure 14 will provide constant ripple over varying VO.

Product Folder Links: LM3429 LM3429-Q1

VSNS = 1.24V x RCSH

RHSP

ICSH = RHSP

VSNS

SW CR 25

( )

OOIN VVV25 -

f=2

INTT VCR xx

fSW = 25 x VIN - VO

RT x CT X VIN

( )

LM3429

RCT

Start tON

VIN/25

Reset timer

RSNS

VIN

LED-

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Feature Description (continued)

Figure 14. Off-timer Circuitry for Buck Regulators

The switching frequency is defined:

Buck (Constant Ripple vs. VIN)

(4)

Buck (Constant Ripple vs. VO)

(5)

Boost and Buck-Boost

(6)

For all topologies, the CTcapacitor is recommended to be 1 nF and should be located very close to the LM3429.

7.3.4 Average LED Current

The LM3429 uses an external current sense resistor (RSNS) placed in series with the LED load to convert the

LED current (ILED) into a voltage (VSNS) as shown in Figure 15. The HSP and HSN pins are the inputs to the

high-side sense amplifier which are forced to be equal potential (VHSP=VHSN) through negative feedback.

Because of this, the VSNS voltage is forced across RHSP to generate the signal current (ICSH) which flows out of

the CSH pin and through the RCSH resistor. The error amplifier will regulate the CSH pin to 1.24 V, therefore ICSH

can be calculated:

(7)

This means VSNS will be regulated as follows:

(8)

ILED can then be calculated:

Product Folder Links: LM3429 LM3429-Q1

RSNS

ILED RHSP

RHSN HSN

HSP High-Side

Sense Amplifier

CSH 1.24V

CCMP

RCSH

COMP

Error Amplifier

VSNS

To PWM

Comparator

LM3429

ICSH

ILED = RSNS

1.24V

RSNS

VSNS RCSH

RHSP

= x

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

Feature Description (continued)

(9)

The selection of the three resistors (RSNS, RCSH, and RHSP) is not arbitrary. For matching and noise performance,

the suggested signal current ICSH is approximately 100 µA. This current does not flow in the LEDs and will not

affect either the off state LED current or the regulated LED current. ICSH can be above or below this value, but

the high-side amplifier offset characteristics may be affected slightly. In addition, to minimize the effect of the

high-side amplifier voltage offset on LED current accuracy, the minimum VSNS is suggested to be 50 mV. Finally,

a resistor (RHSN = RHSP) should be placed in series with the HSN pin to cancel out the effects of the input bias

current (~10 µA) of both inputs of the high-side sense amplifier. The CSH pin can also be used as a low-side

current sense input regulated to 1.24 V. The high-side sense amplifier is disabled if HSP and HSN are tied to

GND.

Figure 15. LED Current Sense Circuitry

7.3.5 Analog Dimming

The CSH pin can be used to analog dim the LED current by adjusting the current sense voltage (VSNS). There

are several different methods to adjust VSNS using the CSH pin:

1. External variable resistance : Adjust a potentiometer placed in series with RCSH to vary VSNS.

2. External variable current source: Source current (0 µA to ICSH) into the CSH pin to adjust VSNS.

In general, analog dimming applications require a lower switching frequency to minimize the effect of the leading

edge blanking circuit. As the LED current is reduced, the output voltage and the duty cycle decreases.

Eventually, the minimum on-time is reached. The lower the switching frequency, the wider the linear dimming

range. Figure 16 shows how both methods are physically implemented.

Method 1 uses an external potentiometer in the CSH path which is a simple addition to the existing circuitry.

However, the LEDs cannot dim completely because there is always some resistance causing signal current to

flow. This method is also susceptible to noise coupling at the CSH pin because the potentiometer increases the

size of the signal current loop.

Method 2 provides a complete dimming range and better noise performance, though it is more complex. It

consists of a PNP current mirror and a bias network consisting of an NPN, 2 resistors and a potentiometer

(RADJ), where RADJ controls the amount of current sourced into the CSH pin. A higher resistance value will source

more current into the CSH pin causing less regulated signal current through RHSP, effectively dimming the LEDs.

VREF should be a precise external voltage reference, while Q7 and Q8 should be a dual pair PNP for best

matching and performance. The additional current (IADD) sourced into the CSH pin can be calculated:

Product Folder Links: LM3429 LM3429-Q1

CSH

RCSH

LM3429

VCC

RBIAS

RMAX

VREF

RADJ

Variable Current Source

Variable

Resistance

RHSP

ILED = ICSH - IADD x RSNS ¸

( )

RADJ x VREF

IADD = RADJ + RMAX - VBE-Q6

RBIAS

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Feature Description (continued)

(10)

The corresponding ILED for a specific IADD is:

(11)

Figure 16. Analog Dimming Circuitry

7.3.6 Current Sense and Current Limit

The LM3429 achieves peak current mode control using a comparator that monitors the MosFET transistor

current, comparing it with the COMP pin voltage as shown in Figure 17. Further, it incorporates a cycle-by-cycle

overcurrent protection function. Current limit is accomplished by a redundant internal current sense comparator.

If the voltage at the current sense comparator input (IS) exceeds 245 mV (typical), the on cycle is immediately

terminated. The IS input pin has an internal N-channel MosFET which pulls it down at the conclusion of every

cycle. The discharge device remains on an additional 250 ns (typical) after the beginning of a new cycle to blank

the leading edge spike on the current sense signal. The leading edge blanking (LEB) determines the minimum

achievable on-time (tON-MIN).

Product Folder Links: LM3429 LM3429-Q1

§+s

1Z1P ¸

T¨

§-s

1Z1Z ¸

ILIM = 245 mV

RLIM

LM3429

PWM

COMP

RLIM

Q1 GATE

LEB

PGND

245 mV

800 mV

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

Feature Description (continued)

Figure 17. Current Sense / Current Limit Circuitry

There are two possible methods to sense the transistor current. The RDS-ON of the main power MosFET can be

used as the current sense resistance because the IS pin was designed to withstand the high voltages present on

the drain when the MosFET is in the off state. Alternatively, a sense resistor located in the source of the MosFET

may be used for current sensing, however a low inductance (ESL) type is suggested. The cycle-by-cycle current

limit (ILIM) can be calulated using either method as the limiting resistance (RLIM):

(12)

In general, the external series resistor allows for more design flexibility, however it is important to ensure all of

the noise sensitive low power ground connections are connected together local to the controller and a single

connection is made to the high current PGND (sense resistor ground point).

7.3.7 Control Loop Compensation

The LM3429 control loop is modeled like any current mode controller. Using a first order approximation, the

uncompensated loop can be modeled as a single pole created by the output capacitor and, in the boost and

buck-boost topologies, a right half plane zero created by the inductor, where both have a dependence on the

LED string dynamic resistance. There is also a high frequency pole in the model, however it is above the

switching frequency and plays no part in the compensation design process therefore it will be neglected.

Because ceramic capacitance is recommended for use with LED drivers due to long lifetimes and high ripple

current rating, the ESR of the output capacitor can also be neglected in the loop analysis. Finally, there is a DC

gain of the uncompensated loop which is dependent on internal controller gains and the external sensing

network.

A buck-boost regulator will be used as an example case. See the Typical Applications section for compensation

of all topologies.

The uncompensated loop gain for a buck-boost regulator is given by the following equation:

(13)

Where the uncompensated DC loop gain of the system is described as:

Product Folder Links: LM3429 LM3429-Q1

PHASE (°)

FREQUENCY (Hz)

GAIN (dB)

100

-20

-40

-60

135

-45

-90

-135

-180

-225

1e-1 1e1 1e3 1e5 1e7

0° Phase Margin

öP1

PHASE

GAIN

öZ1

=Dr 2

ZL1Dx

1P =Z1+D

OD Cr x

T=SNSCSH RR500VD xxx

c620VD x

( ) LIM

LED RID1 xx+

( ) LIMHSP RRD1 xx+

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Feature Description (continued)

(14)

And the output pole (ωP1) is approximated:

(15)

And the right half plane zero (ωZ1) is:

(16)

Figure 18. Uncompensated Loop Gain Frequency Response

Figure 18 shows the uncompensated loop gain in a worst-case scenario when the RHP zero is below the output

pole. This occurs at high duty cycles when the regulator is trying to boost the output voltage significantly. The

RHP zero adds 20dB/decade of gain while loosing 45°/decade of phase which places the crossover frequency

(when the gain is zero dB) extremely high because the gain only starts falling again due to the high frequency

pole (not modeled or shown in figure). The phase will be below -180° at the crossover frequency which means

there is no phase margin (180° + phase at crossover frequency) causing system instability. Even if the output

pole is below the RHP zero, the phase will still reach -180° before the crossover frequency in most cases yielding

instability.

Product Folder Links: LM3429 LM3429-Q1

x= 0U

TT -1 ¸

§s

xx +1 ¸

§s

Z3P

+1 ¸

§s

Z2P

+1 ¸

§s

Z1P

3P =Z

FSFS CR x

P2 6CMP

5x10 x C

RSNS

ILED RHSP

RHSN HSN

HSP High-Side

Sense Amplifier

CSH 1.24V

CCMP

RCSH

COMP

Error Amplifier

VSNS

To PWM

Comparator

LM3429

CFS

RFS

sets öP3

sets öP2

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

Feature Description (continued)

Figure 19. Compensation Circuitry

To mitigate this problem, a compensator should be designed to give adequate phase margin (above 45°) at the

crossover frequency. A simple compensator using a single capacitor at the COMP pin (CCMP) will add a dominant

pole to the system, which will ensure adequate phase margin if placed low enough. At high duty cycles (as

shown in Figure 18), the RHP zero places extreme limits on the achievable bandwidth with this type of

compensation. However, because an LED driver is essentially free of output transients (except catastrophic

failures open or short), the dominant pole approach, even with reduced bandwidth, is usually the best approach.

The dominant compensation pole (ωP2) is determined by CCMP and the output resistance (RO) of the error

amplifier (typically 5 MΩ):

(17)

It may also be necessary to add one final pole at least one decade above the crossover frequency to attenuate

switching noise and, in some cases, provide better gain margin. This pole can be placed across RSNS to filter the

ESL of the sense resistor at the same time. Figure 19 shows how the compensation is physically implemented in

the system.

The high frequency pole (ωP3) can be calculated:

(18)

The total system transfer function becomes:

(19)

The resulting compensated loop gain frequency response shown in Figure 20 indicates that the system has

adequate phase margin (above 45°) if the dominant compensation pole is placed low enough, ensuring stability:

Product Folder Links: LM3429 LM3429-Q1

1.24V

20 PA

LM3429

ROV2

ROV1

OVLO

OVP

PHASE (°)

FREQUENCY (Hz)

GAIN (dB)

-20

-40

-60

-80

-45

-90

-135

-180

-225

-270

1e-1 1e1 1e3 1e5 1e7

GAIN

60° Phase Margin

PHASE

öP2

öP3

öP1

öZ1

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Feature Description (continued)

Figure 20. Compensated Loop Gain Frequency Response

7.3.8 Output Overvoltage Lockout (OVLO)

The LM3429 can be configured to detect an output (or input) overvoltage condition through the OVP pin. The pin

features a precision 1.24-V threshold with 20 µA (typical) of hysteresis current as shown in Figure 21. When the

OVLO threshold is exceeded, the GATE pin is immediately pulled low and a 20 µA current source provides

hysteresis to the lower threshold of the OVLO hysteretic band.

Figure 21. Overvoltage Protection Circuitry

If the LEDs are referenced to a potential other than ground (floating), as in the buck-boost and buck

configuration, the output voltage (VO) should be sensed and translated to ground by using a single PNP as

shown in Figure 22.

Product Folder Links: LM3429 LM3429-Q1

1.24V

20 PA

LM3429

RUV2

RUV1

VIN

UVLO

nDIM

RUVH

(optional)

2OVHYSO RA20V xP=

-OFFTURN 24V.1V x+

OV1 OV2

R5.0 R

1OV

1¸

-OFFTURN 24V.1V 1OV

R+2OVOV RR

LM3429

OVP

ROV2

ROV1

LED+

LED-

LM3429

LM3429-Q1

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SNVS616H –APRIL 2009–REVISED JULY 2015

Feature Description (continued)

Figure 22. Floating Output OVP Circuitry

The overvoltage turnoff threshold (VTURN-OFF) is defined as follows:

Ground Referenced

(20)

Floating

(21)

In the ground referenced configuration, the voltage across ROV2 is VO- 1.24 V whereas in the floating

configuration it is VO- 620 mV where 620 mV approximates the VBE of the PNP transistor.

The overvoltage hysteresis (VHYSO) is defined as follows:

(22)

7.3.9 Input Undervoltage Lockout (UVLO)

The nDIM pin is a dual-function input that features an accurate 1.24 V threshold with programmable hysteresis

as shown in Figure 23. This pin functions as both the PWM dimming input for the LEDs and as a VIN UVLO.

When the pin voltage rises and exceeds the 1.24 V threshold, 20 µA (typical) of current is driven out of the nDIM

pin into the resistor divider providing programmable hysteresis.

Figure 23. UVLO Circuit

Product Folder Links: LM3429 LM3429-Q1

LM3429

RUV2

RUV1

VIN

nDIM

RUVH

QDIM

DDIM

Inverted

PWM

Standard

PWM

PA20

HYS

V¨

§+

2UV

R¸

1UV

x1UV

2UV

UVH

2UV

RA20 x

HYS

1¸

-ONTURN 24V.1V 1UV

R+2UVUV RR

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Feature Description (continued)

When using the nDIM pin for UVLO and PWM dimming concurrently, the UVLO circuit can have an extra series

resistor to set the hysteresis. This allows the standard resistor divider to have smaller resistor values minimizing

PWM delays due to a pulldown MosFET at the nDIM pin (see PWM Dimming section). In general, at least 3V of

hysteresis is necessary when PWM dimming if operating near the UVLO threshold.

The turn-on threshold (VTURN-ON) is defined as follows:

(23)

The hysteresis (VHYS) is defined as follows:

UVLO Only

(24)

PWM Dimming and UVLO

(25)

7.3.10 PWM Dimming

The active low nDIM pin can be driven with a PWM signal which controls the main NFET (Q1). The brightness of

the LEDs can be varied by modulating the duty cycle of this signal. LED brightness is approximately proportional

to the PWM signal duty cycle, so 30% duty cycle equals approximately 30% LED brightness. This function can

be ignored if PWM dimming is not required by using nDIM solely as a VIN UVLO input as described in the Input

Undervoltage Lockout (UVLO) section or by tying it directly to VCC or VIN (if less than 76VDC).

Figure 24. PWM Dimming Circuit

Figure 24 shows two ways the PWM signal can be applied to the nDIM pin:

1. Connect the dimming MosFET (QDIM) with the drain to the nDIM pin and the source to GND. Apply an

external logic-level PWM signal to the gate of QDIM. A pull down resistor may be necessary to properly turn

off QDIM if no signal is present.

2. Connect the anode of a Schottky diode (DDIM) to the nDIM pin. Apply an external inverted logic-level PWM

signal to the cathode of the same diode.

A minimum on-time must be maintained in order for PWM dimming to operate in the linear region of its transfer

function. Because the controller is disabled during dimming, the PWM pulse must be long enough such that the

energy intercepted from the input is greater than or equal to the energy being put into the LEDs. For boost and

buck-boost regulators, the following condition must be maintained:

Product Folder Links: LM3429 LM3429-Q1

tPULSE = 2 x ILED x VO X L1

VIN2

LM3429

LM3429-Q1

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SNVS616H –APRIL 2009–REVISED JULY 2015

Feature Description (continued)

(26)

In the previous equation, tPULSE is the length of the PWM pulse in seconds.

7.3.11 Startup Regulator (VCC LDO)

The LM3429 includes a high voltage, low dropout (LDO) bias regulator. When power is applied, the regulator is

enabled and sources current into an external capacitor connected to the VCC pin. The VCC output voltage is 6.9V

nominally and the supply is internally current limited to 20 mA (minimum). The recommended bypass

capacitance range for the VCC regulator is 2.2 µF to 3.3 µF. The output of the VCC regulator is monitored by an

internal UVLO circuit that protects the device during startup, normal operation, and shutdown from attempting to

operate with insufficient supply voltage.

7.3.12 Thermal Shutdown

The LM3429 includes thermal shutdown. If the die temperature reaches approximately 165°C the device will shut

down (GATE pin low), until it reaches approximately 140°C where it turns on again.

7.4 Device Functional Modes

This device has no functional modes.

Product Folder Links: LM3429 LM3429-Q1

LM3429

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SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

8.1.1 Inductor

The inductor (L1) is the main energy storage device in a switching regulator. Depending on the topology, energy

is stored in the inductor and transfered to the load in different ways (as an example, buck-boost operation is

detailed in the Current Regulators section). The size of the inductor, the voltage across it, and the length of the

switching subinterval (tON or tOFF) determines the inductor current ripple (ΔiL-PP). In the design process, L1 is

chosen to provide a desired ΔiL-PP. For a buck regulator the inductor has a direct connection to the load, which is

good for a current regulator. This requires little to no output capacitance therefore ΔiL-PP is basically equal to the

LED ripple current ΔiLED-PP. However, for boost and buck-boost regulators, there is always an output capacitor

which reduces ΔiLED-PP, therefore the inductor ripple can be larger than in the buck regulator case where output

capacitance is minimal or completely absent.

In general, ΔiLED-PP is recommended by manufacturers to be less than 40% of the average LED current (ILED).

Therefore, for the buck regulator with no output capacitance, ΔiL-PP should also be less than 40% of ILED. For the

boost and buck-boost topologies, ΔiL-PP can be much higher depending on the output capacitance value.

However, ΔiL-PP is suggested to be less than 100% of the average inductor current (IL) to limit the RMS inductor

current.

L1 is also suggested to have an RMS current rating at least 25% higher than the calculated minimum allowable

RMS inductor current (IL-RMS).

8.1.2 LED Dynamic Resistance (rD)

When the load is a string of LEDs, the output load resistance is the LED string dynamic resistance plus RSNS.

LEDs are PN junction diodes, and their dynamic resistance shifts as their forward current changes. Dividing the

forward voltage of a single LED (VLED) by the forward current (ILED) leads to an incorrect calculation of the

dynamic resistance of a single LED (rLED). The result can be 5 to 10 times higher than the true rLED value.

Figure 25. Dynamic Resistance

Obtaining rLED is accomplished by referring to the manufacturer's LED I-V characteristic. It can be calculated as

the slope at the nominal operating point as shown in Figure 25. For any application with more than 2 series

LEDs, RSNS can be neglected allowing rDto be approximated as the number of LEDs multiplied by rLED.

Product Folder Links: LM3429 LM3429-Q1

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SNVS616H –APRIL 2009–REVISED JULY 2015

Application Information (continued)

8.1.3 Output Capacitor

For boost and buck-boost regulators, the output capacitor (CO) provides energy to the load when the recirculating

diode (D1) is reverse biased during the first switching subinterval. An output capacitor in a buck topology will

simply reduce the LED current ripple (ΔiLED-PP) below the inductor current ripple (ΔiL-PP). In all cases, COis sized

to provide a desired ΔiLED-PP. As mentioned in the Inductor section, ΔiLED-PP is recommended by manufacturers to

be less than 40% of the average LED current (ILED).

COshould be carefully chosen to account for derating due to temperature and operating voltage. It must also

have the necessary RMS current rating. Ceramic capacitors are the best choice due to their high ripple current

rating, long lifetime, and good temperature performance. An X7R dieletric rating is suggested.

8.1.4 Input Capacitors

The input capacitance (CIN) provides energy during the discontinuous portions of the switching period. For buck

and buck-boost regulators, CIN provides energy during tON and during tOFF, the input voltage source charges up

CIN with the average input current (IIN). For boost regulators, CIN only needs to provide the ripple current due to

the direct connection to the inductor. CIN is selected given the maximum input voltage ripple (ΔvIN-PP) which can

be tolerated. ΔvIN-PP is suggested to be less than 10% of the input voltage (VIN).

An input capacitance at least 100% greater than the calculated CIN value is recommended to account for derating

due to temperature and operating voltage. When PWM dimming, even more capacitance can be helpful to

minimize the large current draw from the input voltage source during the rising transition of the LED current

waveform.

The chosen input capacitors must also have the necessary RMS current rating. Ceramic capacitors are again the

best choice due to their high ripple current rating, long lifetime, and good temperature performance. An X7R

dieletric rating is suggested.

For most applications, TI recommends bypassing the VIN pin with an 0.1-µF ceramic capacitor placed as close as

possible to the pin. In situations where the bulk input capacitance may be far from the LM3429 device, a 10-Ω

series resistor can be placed between the bulk input capacitance and the bypass capacitor, creating a 150 kHz

filter to eliminate undesired high frequency noise coupling.

8.1.5 N-Channel MosFET (NFET)

The LM3429 requires an external NFET (Q1) as the main power MosFET for the switching regulator. Q1 is

recommended to have a voltage rating at least 15% higher than the maximum transistor voltage to ensure safe

operation during the ringing of the switch node. In practice, all switching regulators have some ringing at the

switch node due to the diode parasitic capacitance and the lead inductance. The current rating is recommended

to be at least 10% higher than the average transistor current. The power rating is then verified by calculating the

power loss given the RMS transistor current and the NFET on-resistance (RDS-ON).

In general, the NFET should be chosen to minimize total gate charge (Qg) whenever switching frequencies are

high and minimize RDS-ON otherwise. This will minimize the dominant power losses in the system. Frequently,

higher current NFETs in larger packages are chosen for better thermal performance.

8.1.6 Re-Circulating Diode

A re-circulating diode (D1) is required to carry the inductor current during tOFF. The most efficient choice for D1 is

a Schottky diode due to low forward voltage drop and near-zero reverse recovery time. Similar to Q1, D1 is

recommended to have a voltage rating at least 15% higher than the maximum transistor voltage to ensure safe

operation during the ringing of the switch node and a current rating at least 10% higher than the average diode

current. The power rating is verified by calculating the power loss through the diode. This is accomplished by

checking the typical diode forward voltage from the I-V curve on the product data sheet and multiplying by the

average diode current. In general, higher current diodes have a lower forward voltage and come in better

performing packages minimizing both power losses and temperature rise.

Product Folder Links: LM3429 LM3429-Q1

ILED

ROV1

ROV2

RSNS

OVP

LM3429

nDIM

VIN

PGND

DAP

GATE

COMP

CSH

RCT

HSN

HSP

CIN

CBYP

RLIM

CCMP

RCSH

RUV2

RUV1

RHSN

RHSP

AGND

RUVH

PWM

RFS

CFS

COV

VIN

VCC

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

8.2 Typical Applications

8.2.1 Basic Topology Schematics

Figure 26. Boost Regulator (VIN < VO)

Product Folder Links: LM3429 LM3429-Q1

OVP

LM3429

nDIM

VIN

PGND

DAP

GATE

COMP

CSH

RCT

HSN

HSP

CIN

CBYP

RLIM

CCMP

RCSH

RUV2

RUV1

RHSN

RHSP

ILED

ROV2

RSNS

AGND

RUVH

PWM

RFS

CFS

VIN

ROV1

COV

VCC

LM3429

LM3429-Q1

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SNVS616H –APRIL 2009–REVISED JULY 2015

Typical Applications (continued)

Figure 27. Buck Regulator (VIN > VO)

Product Folder Links: LM3429 LM3429-Q1

VIN

OVP

LM3429

nDIM

VIN

PGND

DAP

GATE

COMP

CSH

RCT

HSN

HSP

CIN

CBYP

RLIM

CCMP

RCSH

RUV2

RUV1

RHSN

RHSP

ILED

AGND

RUVH

PWM

ROV2

ROV1

COV

VIN

RSNS

RFS

CFS

VIN

VCC

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

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Typical Applications (continued)

Figure 28. Buck-Boost Regulator

8.2.1.1 Design Requirements

Number of series LEDs: N

Single LED forward voltage: VLED

Single LED dynamic resistance: rLED

Nominal input voltage: VIN

Input voltage range: VIN-MAX, VIN-MIN

Switching frequency: fSW

Current sense voltage: VSNS

Average LED current: ILED

Inductor current ripple: ΔiL-PP

LED current ripple: ΔiLED-PP

Peak current limit: ILIM

Input voltage ripple: ΔvIN-PP

Output OVLO characteristics: VTURN-OFF, VHYSO

Input UVLO characteristics: VTURN-ON, VHYS

Product Folder Links: LM3429 LM3429-Q1

SNS

R = SNS

LED

T25

R = TSW Cf x

( )

T25

R=2

OOIN VVV -

xx 2

INTSW VCf xx

RT = 25 x VIN - VO

fSW x CT X VIN

( )

D=INO VV +

D= INO VV -

D= O

rD = N x rLED

VO = N x VLED

LM3429

LM3429-Q1

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SNVS616H –APRIL 2009–REVISED JULY 2015

Typical Applications (continued)

8.2.1.2 Detailed Design Procedure

8.2.1.2.1 Operating Point

Given the number of series LEDs (N), the forward voltage (VLED) and dynamic resistance (rLED) for a single LED,

solve for the nominal output voltage (VO) and the nominal LED string dynamic resistance (rD):

(27)

(28)

Solve for the ideal nominal duty cycle (D):

Buck

(29)

Boost

(30)

Buck-boost

(31)

Using the same equations, find the minimum duty cycle (DMIN) using maximum input voltage (VIN-MAX) and the

maximum duty cycle (DMAX) using the minimum input voltage (VIN-MIN). Also, remember that D' = 1 - D.

8.2.1.2.2 Switching Frequency

Set the switching frequency (fSW) by assuming a CTvalue of 1 nF and solving for RT:

Buck (Constant Ripple vs. VIN)

(32)

Buck (Constant Ripple vs. VO)

(33)

Boost and Buck-Boost

(34)

8.2.1.2.3 Average LED Current

For all topologies, set the average LED current (ILED) knowing the desired current sense voltage (VSNS) and

solving for RSNS:

(35)

If the calculated RSNS is too far from a desired standard value, then VSNS must be adjusted to obtain a standard

value.

Product Folder Links: LM3429 LM3429-Q1

IRMSCO =

-12PP-LED

iü

LED

oD LED PP

I x D

Cr x i 

C = PPL

PPLEDDSW irf8 -

'xxx

IL-RMS = 1 + 1

12 xILED

'IL-PP x D' ¸

§2

ILED x

IL-RMS = ILED x 1 + 1

12 xILED

'IL-PP

§2

L PP SW

V x D

L1 i x f



IN O

L PP SW

(V V )xD

L1 i x f



1.24V

RHSP =RRI SNSCSHLED xx

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Typical Applications (continued)

Setup the suggested signal current of 100 µA by assuming RCSH = 12.4 kΩand solving for RHSP:

(36)

If the calculated RHSP is too far from a desired standard value, then RCSH can be adjusted to obtain a standard

value.

8.2.1.2.4 Inductor Ripple Current

Set the nominal inductor ripple current (ΔiL-PP) by solving for the appropriate inductor (L1):

Buck

(37)

Boost and Buck-Boost

(38)

To set the worst case inductor ripple current, use VIN-MAX and DMIN when solving for L1.

The minimum allowable inductor RMS current rating (IL-RMS) can be calculated as:

Buck

(39)

Boost and Buck-Boost

(40)

8.2.1.2.5 LED Ripple Current

Set the nominal LED ripple current (ΔiLED-PP), by solving for the output capacitance (CO):

Buck

(41)

Boost and Buck-Boost

(42)

To set the worst case LED ripple current, use DMAX when solving for CO.

The minimum allowable RMS output capacitor current rating (ICO-RMS) can be approximated:

Buck

(43)

Product Folder Links: LM3429 LM3429-Q1

=Dr 2

ZL1Dx

=Dr 2

ZL1

1P =Z1+D

OD Cr x

1P =Z2

OD Cr x

1P =Z1

OD Cr x

§+s

1Z1P ¸

T¨

§-s

1Z1Z ¸

§+s

1Z1P ¸

LIM

R=LIM

245 mV

1-DMAX

DMAX

ICO-RMS = ILED x

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

Typical Applications (continued)

Boost and Buck-boost

(44)

8.2.1.2.6 Peak Current Limit

Set the peak current limit (ILIM) by solving for the transistor path sense resistor (RLIM):

(45)

8.2.1.2.7 Loop Compensation

Using a simple first order peak current mode control model, neglecting any output capacitor ESR dynamics, the

necessary loop compensation can be determined.

First, the uncompensated loop gain (TU) of the regulator can be approximated:

Buck

(46)

Boost and Buck-Boost

(47)

Where the pole (ωP1) is approximated:

Buck

(48)

Boost

(49)

Buck-Boost

(50)

And the RHP zero (ωZ1) is approximated:

Boost

(51)

Buck-Boost

(52)

Product Folder Links: LM3429 LM3429-Q1

x= 0U

TT -1 ¸

§s

xx +1 ¸

§s

Z3P

+1 ¸

§s

Z2P

+1 ¸

§s

Z1P

x= 0U

TT 1

xx +1 ¸

§s

Z3P

+1 ¸

§s

Z2P

+1 ¸

§s

Z1P

CFS 3P

10xZ

max

3P =

Z( ) 10, 1Z1P x

CMP

C=6

5×10

1Z1P )

,min( Z

5x0U

2P =

T=SNSCSH RR500VD xxx

c620VD x

( ) LIM

LED RID1 xx+

( ) LIMHSP RRD1 xx+

T=SNSCSH RR500VD xxx

c310VD x

LIMLED RI x

LIMHSP RR2 xx

SNS 620V

RR500V =

xx CSH

LIMLED RI x

T=LIMHSP RR x

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Typical Applications (continued)

And the uncompensated DC loop gain (TU0) is approximated:

Buck

(53)

Boost

(54)

Buck-Boost

(55)

For all topologies, the primary method of compensation is to place a low-frequency dominant pole (ωP2) which

will ensure that there is ample phase margin at the crossover frequency. This is accomplished by placing a

capacitor (CCMP) from the COMP pin to GND, which is calculated according to the lower value of the pole and the

RHP zero of the system (shown as a minimizing function):

(56)

(57)

If analog dimming is used, CCMP should be approximately 4x larger to maintain stability as the LEDs are dimmed

to zero.

A high frequency compensation pole (ωP3) can be used to attenuate switching noise and provide better gain

margin. Assuming RFS = 10 Ω, CFS is calculated according to the higher value of the pole and the RHP zero of

the system (shown as a maximizing function):

(58)

(59)

The total system loop gain (T) can then be written as:

Buck

(60)

Boost and Buck-boost

(61)

8.2.1.2.8 Input Capacitance

Set the nominal input voltage ripple (ΔvIN-PP) by solving for the required capacitance (CIN):

Buck

Product Folder Links: LM3429 LM3429-Q1

IT-MAX = x ILED

1 - DMAX

DMAX

IT-MAX = DMAX x ILED

OMAXINMAXT VVV +

=--

MAXT

V-

MAXINMAXT VV -- =

1-DMAX

DMAX

ICIN-RMS = ILED x

ICIN-RMS = 'iL-PP

(1-DMID)DII LEDRMSCIN xx=

- MID

CIN = 'VIN-PP x fSW

ILED x D

CIN = 8 x 'VIN-PP x fSW

'iL-PP

CIN = ILED x (1 - D) x D

'VIN-PP x fSW

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

Typical Applications (continued)

(62)

Boost

(63)

Buck-Boost

(64)

Use DMAX to set the worst case input voltage ripple, when solving for CIN in a buck-boost regulator and DMID = 0.5

when solving for CIN in a buck regulator.

The minimum allowable RMS input current rating (ICIN-RMS) can be approximated:

Buck

(65)

Boost

(66)

Buck-Boost

(67)

8.2.1.2.9 NFET

The NFET voltage rating should be at least 15% higher than the maximum NFET drain-to-source voltage (VT-

MAX):

Buck

(68)

Boost

(69)

Buck-Boost

(70)

The current rating should be at least 10% higher than the maximum average NFET current (IT-MAX):

Buck

(71)

Boost and Buck-Boost

(72)

Approximate the nominal RMS transistor current (IT-RMS) :

Buck

Product Folder Links: LM3429 LM3429-Q1

ROV1=R1.24V OV2

xVm620V OFFTURN -

ROV1 =1.24VV OFFTURN -

R1.24V OV2

ROV2 =VHYSO

A20P

FDDD VIP x=

ID-MAX = ILED

ID-MAX = (1 - DMIN) x ILED

VRD-MAX = VIN-MAX + VO

VRD-MAX = VO

VRD-MAX = VIN-MAX

DSON

RMSTT RIP x= -

IRMST =

-D

ILED

DIT- ILEDRMS x=

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Typical Applications (continued)

(73)

Boost and Buck-Boost

(74)

Given an NFET with on-resistance (RDS-ON), solve for the nominal power dissipation (PT):

(75)

8.2.1.2.10 Diode

The Schottky diode voltage rating should be at least 15% higher than the maximum blocking voltage (VRD-MAX):

Buck

(76)

Boost

(77)

Buck-Boost

(78)

The current rating should be at least 10% higher than the maximum average diode current (ID-MAX):

Buck

(79)

Boost and Buck-Boost

(80)

Replace DMAX with D in the ID-MAX equation to solve for the average diode current (ID). Given a diode with forward

voltage (VFD), solve for the nominal power dissipation (PD):

(81)

8.2.1.2.11 Output OVLO

For boost and buck-boost regulators, output OVLO is programmed with the turn-off threshold voltage (VTURN-OFF)

and the desired hysteresis (VHYSO). To set VHYSO, solve for ROV2:

(82)

To set VTURN-OFF, solve for ROV1:

Boost

(83)

Buck-Boost

(84)

Product Folder Links: LM3429 LM3429-Q1

( )

RR +x 2UV1UV

A20P

( )

xHYS A20V xP- R 2UV

R1UV

UVH

R =

RUV1 =1.24VV ONTURN -

R1.24V UV2

RUV2 =A20P

VHYS

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

Typical Applications (continued)

A small filter capacitor (COVP = 47 pF) should be added from the OVP pin to ground to reduce coupled switching

noise.

8.2.1.2.12 Input UVLO

For all topologies, input UVLO is programmed with the turn-on threshold voltage (VTURN-ON) and the desired

hysteresis (VHYS).

Method #1: If no PWM dimming is required, a two resistor network can be used. To set VHYS, solve for RUV2:

(85)

To set VTURN-ON, solve for RUV1:

(86)

Method #2: If PWM dimming is required, a three resistor network is suggested. To set VTURN-ON, assume RUV2 =

10 kΩand solve for RUV1 as in Method #1. To set VHYS, solve for RUVH:

(87)

8.2.1.2.13 PWM Dimming Method

PWM dimming can be performed several ways:

Method #1: Connect the dimming MosFET (Q3) with the drain to the nDIM pin and the source to GND. Apply an

external PWM signal to the gate of QDIM. A pull down resistor may be necessary to properly turn off Q3.

Method #2: Connect the anode of a Schottky diode to the nDIM pin. Apply an external inverted PWM signal to

the cathode of the same diode.

8.2.1.2.14 Analog Dimming Method

Analog dimming can be performed several ways:

Method #1: Place a potentiometer in series with the RCSH resistor to dim the LED current from the nominal ILED

to near zero.

Method #2: Connect a controlled current source as detailed in the Analog Dimming section to the CSH pin.

Increasing the current sourced into the CSH node will decrease the LEDs from the nominal ILED to zero current.

Product Folder Links: LM3429 LM3429-Q1

OVP

LM3429

nDIM

PGND

DAP

GATE

COMP

CSH

RCT

HSN

HSP

CIN

CBYP

CCMP

RCSH

RUV2

RUV1

RHSN

RHSP

RSNS

AGND

RFS

CFS

ILED

ROV2

ROV1

COV

VIN

10V ± 70V

VIN

VCC

RLIM

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Typical Applications (continued)

8.2.2 Buck-Boost Application - 6 LEDs at 1 A

Figure 29. Buck-Boost Application - 6 LEDs at 1 A Schematic

8.2.2.1 Design Requirements

N=6

VLED = 3.5 V

rLED = 325 mΩ

VIN = 24 V

VIN-MIN = 10 V

VIN-MAX = 70 V

fSW = 700 kHz

VSNS = 100 mV

ILED = 1A

ΔiL-PP = 500 mA

ΔiLED-PP = 50 mA

ΔvIN-PP = 100 mV

ILIM = 6A

VTURN-ON = 10 V

VHYS =3V

Product Folder Links: LM3429 LM3429-Q1

ILED = = k0.11.24V :xA0.1=

k4.121.0 :x:

RR CSHSNS xR1.24V HSP

=1.24V1.24V

RHSP :

=k0.1

x0.1k12.4A1

xx RRI SNSCSHLED

=== 1.0

RSNS ILED

mV100

VSNS

CT = 1 nF

RT = 35.7 k:

2525 =35.7 k: x 1 nF

fSW = RT x CT= 700 kHz

2525 =700 kHz x 1 nF = 35.7 k:

RT =fSW x CT

DMAX == 677.0

V21 V10V21 +

VV IN-MINO +

21V

=21V + 70V = 0.231

DMIN = VO + VIN-MAX

533.0467.01D1'D =

D== 467.0

V21 V24V21 +

VOVV INO +

=95.1m3256rNr LEDD

V21V5.36VNV LEDO =

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

Typical Applications (continued)

VTURN-OFF = 40 V

VHYSO = 10 V

8.2.2.2 Detailed Design Procedure

8.2.2.2.1 Operating Point

Solve for VOand rD:

(88)

(89)

Solve for D, D', DMAX, and DMIN:

(90)

(91)

(92)

(93)

8.2.2.2.2 Switching Frequency

Assume CT= 1 nF and solve for RT:

(94)

The closest standard resistor is actually 35.7 kΩtherefore the fSW is:

(95)

The chosen components from step 2 are:

(96)

8.2.2.2.3 Average LED Current

Solve for RSNS:

(97)

Assume RCSH = 12.4 kΩand solve for RHSP:

(98)

The closest standard resistor for RSNS is actually 0.1Ωand for RHSP is actually 1 kΩtherefore ILED is:

(99)

The chosen components from step 3 are:

Product Folder Links: LM3429 LM3429-Q1

F8.6COP=

=ILED

IRMSCO- =

1- 0.677

677.0 1.45A

x1- DMAX

DMAX =

DILED x

'iPP-LED SW

fxrDxCO

= =

kHz00795.1 xx:5 mA

467.0A1 x F8.6 P

'iPP-LED

rSWPP-LEDD xx DILED x

CO=

= F84.6 P=

kHz007mA595.1 xx:

467.0A1 x

H331L P

A88.1

RMSL

ILED

RMSL x

-12

+¸

§Di PPL c

ILED

533.0mA485 2

x¸

§A1

533.0 A1

PP- ==

LDVIN xf1L SW

xkHz007H33 xP

467.0V42 x mA485

== DVIN xfSW

x467.0V42 x PH

1L PP-

'iLkHz007500 mA x

k4.21RCSH =

k1RR HSN ==

HSP

0.1R NSS =:

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Typical Applications (continued)

(100)

8.2.2.2.4 Inductor Ripple Current

Solve for L1:

(101)

The closest standard inductor is 33 µH therefore the actual ΔiL-PP is:

(102)

Determine minimum allowable RMS current rating:

(103)

The chosen component from step 4 is:

(104)

8.2.2.2.5 Output Capacitance

Solve for CO:

(105)

The closest standard capacitor is 6.8 µF therefore the actual ΔiLED-PP is:

(106)

Determine minimum allowable RMS current rating:

(107)

The chosen components from step 5 are:

(108)

Product Folder Links: LM3429 LM3429-Q1

F1.0CFS P=

F0.22CCOMP P=

:10RFS =

= F091.0

1P==CFS 10:xsec

rad

M1.1

10:3P

1010max 1P xZ

=,1Z1P ZZ

sec

rad

k110

=sec

rad

M1.110=

F17.0

CCMP µ===

173.1 sec

rad 6

×Ω

5 10× 6

2P ×ѠΩ5 10×

= = sec

rad

173.1=

sec

rad

k37

56305x56305x 1Z

2P =Z),min( 1Z1P ZZ

T5 0U

=T 0U = 5630=

04.0A1467.1 :

xx V620533.0 x

( )

D1+RI LIMLED xx V620D x

sec

rad

k37=== 533.095.1 2

x:H33467.0 Px

Dr 2

xL1Dx

=sec

rad

= 110k

1 + D

ZP1 = 1.467

1.95: x 6.8 PF

rD x CO

0.04:RLIM =

:04.0 === 6.13A

mV245mV245

ILIM RLIM

:=== 041.0

RLIM mV245mV245

ILIM

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

Typical Applications (continued)

8.2.2.2.6 Peak Current Limit

Solve for RLIM:

(109)

The closest standard resistor is 0.04 Ωtherefore ILIM is:

(110)

The chosen component from step 6 is:

(111)

8.2.2.2.7 Loop Compensation

ωP1 is approximated:

(112)

ωZ1 is approximated:

(113)

TU0 is approximated:

(114)

To ensure stability, calculate ωP2:

(115)

Solve for CCMP:

(116)

To attenuate switching noise, calculate ωP3:

(117)

Assume RFS = 10 Ωand solve for CFS:

(118)

The chosen components from step 7 are:

(119)

Product Folder Links: LM3429 LM3429-Q1

D1 o 12A, 100V, DPAK

mW600mV600A1VIP FDDD =

A1II LEDMAXD ==

V91V21V70VVV OMAXINMAXRD =

=--

Q1 o 32A, 100V, DPAK

mW82m50A28.1RIP 2

DSON

RMSTT =

IRMST =

-ILED

Dc=xA28.1

0.467

533.0

=A2.1A1 =

677.01- 677.0

IMAXT-

V91V21V70VVV OMAXINMAXT =+=+= --

CIN = 3 x 4.7 PF

=ILED

IRMSIN- =

1- 0.677

677.0 1.45A

x1- DMAX

DMAX =

CIN == kHz700mV100 x 467.0A1 x F66.6 P=

'vSWPPIN- x

DILED x

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Typical Applications (continued)

8.2.2.2.8 Input Capacitance

Solve for the minimum CIN:

(120)

To minimize power supply interaction a 200% larger capacitance of approximately 14 µF is used, therefore the

actual ΔvIN-PP is much lower. Because high voltage ceramic capacitor selection is limited, three 4.7 µF X7R

capacitors are chosen.

Determine minimum allowable RMS current rating:

(121)

The chosen components from step 8 are:

(122)

8.2.2.2.9 NFET

Determine minimum Q1 voltage rating and current rating:

(123)

(124)

A 100-V NFET is chosen with a current rating of 32A due to the low RDS-ON = 50 mΩ. Determine IT-RMS and PT:

(125)

(126)

The chosen component from step 9 is:

(127)

8.2.2.2.10 Diode

Determine minimum D1 voltage rating and current rating:

(128)

(129)

A 100-V diode is chosen with a current rating of 12 A and VDF = 600 mV. Determine PD:

(130)

The chosen component from step 10 is:

(131)

8.2.2.2.11 Input UVLO

Solve for RUV2:

Product Folder Links: LM3429 LM3429-Q1

ROV1 = 15.8 k:

ROV2 = 499 k:

= 39.8V

1.24V x (0.5 x 15.8 k: + 499 k:)

VTURN-OFF = 15.8 k:

1.24V x (0.5 x ROV1 + ROV2)

VTURN-OFF = ROV1

:== k15.7

-0.62VV OFFTURN

xR1.24V OV2

=ROV1

:x k4991.24V- 0.62V40V

29.98VA20k499A20RV OVHYSO =

=== A

10V

ROV2 P:k500

VHYSO

A20P

k:501R 2UV =k:12R 1UV =

RUV1

()

RR1.24V UV2UV1+x

VONTURN =

= V10.1=

( )

k150k211.24V :+:xk21 :

VONTURN-

:== k2.21

-1.24VV ONTURN

xR1.24V UV2

=RUV1

:x k1501.24V-1.24V10V

3VA20k150A20RV 2UVHYS =

=PP

=== A

RUV2 P:k150

VHYS

A20P

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

Typical Applications (continued)

(132)

The closest standard resistor is 150 kΩtherefore VHYS is:

(133)

Solve for RUV1:

(134)

The closest standard resistor is 21 kΩmaking VTURN-ON:

(135)

The chosen components from step 11 are:

(136)

8.2.2.2.12 Output OVLO

Solve for ROV2:

(137)

The closest standard resistor is 499 kΩtherefore VHYSO is:

(138)

Solve for ROV1:

(139)

The closest standard resistor is 15.8 kΩmaking VTURN-OFF:

(140)

The chosen components from step 12 are:

(141)

Product Folder Links: LM3429 LM3429-Q1

VIN (V)

EFFICIENCY (%)

100

70 0 16 32 48 64 80

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Typical Applications (continued)

Table 1. Design 1 Bill of Materials

QTY PART ID PART VALUE MANUFACTURER PART NUMBER

1 LM3429 Boost controller TI LM3429MH

1 CCMP 0.22 µF X7R 10% 25 V MURATA GRM21BR71E224KA01L

1 CF2.2 µF X7R 10% 16 V MURATA GRM21BR71C225KA12L

1 CFS 0.1 µF X7R 10% 25 V MURATA GRM21BR71E104KA01L

3 CIN 4.7 µF X7R 10% 100 V TDK C5750X7R2A475K

1 CO6.8 µF X7R 10% 50 V TDK C4532X7R1H685K

1 COV 47 pF COG/NPO 5% 50 V AVX 08055A470JAT2A

1 CT1000 pF COG/NPO 5% 50 V MURATA GRM2165C1H102JA01D

1 D1 Schottky 100 V 12 A VISHAY 12CWQ10FNPBF

1 L1 33 µH 20% 6.3 A COILCRAFT MSS1278-333MLB

1 Q1 NMOS 100 V 32 A FAIRCHILD FDD3682

1 Q2 PNP 150 V 600 m A FAIRCHILD MMBT5401

1 RCSH 12.4 kΩ1% VISHAY CRCW080512K4FKEA

1 RFS 10 Ω1% VISHAY CRCW080510R0FKEA

2 RHSP, RHSN 1 kΩ1% VISHAY CRCW08051K00FKEA

1 RLIM 0.04 Ω1% 1W VISHAY WSL2512R0400FEA

1 ROV1 15.8 kΩ1% VISHAY CRCW080515K8FKEA

1 ROV2 499 kΩ1% VISHAY CRCW0805499KFKEA

1 RSNS 0.1 Ω1% 1W VISHAY WSL2512R1000FEA

1 RT35.7 kΩ1% VISHAY CRCW080535K7FKEA

1 RUV1 21 kΩ1% VISHAY CRCW080521K0FKEA

1 RUV2 150 kΩ1% VISHAY CRCW0805150KFKEA

8.2.2.3 Application Curve

Figure 30. Buck-Boost Efficiency vs Input Voltage, VO= 6 LEDs

Product Folder Links: LM3429 LM3429-Q1

OVP

LM3429

nDIM

VIN

PGND

DAP

GATE

COMP

CSH

RCT

HSN

HSP

CIN

CBYP

RLIM

CCMP

RCSH

RUV2

RUV1

RHSN

RHSP

AGND

RUVH

PWM

RSNS

RFS

CFS

ILED

ROV1

ROV2

COV

VIN

8V - 28V

VCC

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

8.2.3 Boost PWM Dimming Application - 9 LEDs at 1 A

Figure 31. Boost PWM Dimming Application - 9 LEDs at 1 A Schematic

8.2.3.1 Detailed Design Procedure

Table 2. Design 2 Bill of Materials

QTY PART ID PART VALUE MANUFACTURER PART NUMBER

1 LM3429 Boost controller TI LM3429MH

2 CCMP, CFS 0.1 µF X7R 10% 25 V MURATA GRM21BR71E104KA01L

1 CF2.2 µF X7R 10% 16 V MURATA GRM21BR71C225KA12L

2, 1 CIN, CO6.8 µF X7R 10% 50 V TDK C4532X7R1H685K

1 COV 47 pF COG/NPO 5% 50 V AVX 08055A470JAT2A

1 CT1000 pF COG/NPO 5% 50 V MURATA GRM2165C1H102JA01D

1 D1 Schottky 60 V 5 A COMCHIP CDBC560-G

1 L1 33 µH 20% 6.3 A COILCRAFT MSS1278-333MLB

1 Q1 NMOS 60 V 8 A VISHAY SI4436DY

1 Q2 NMOS 60 V 115 mA ON SEMI 2N7002ET1G

2 RCSH, ROV1 12.4 kΩ1% VISHAY CRCW080512K4FKEA

1 RFS 10 Ω1% VISHAY CRCW080510R0FKEA

2 RHSP, RHSN 1 kΩ1% VISHAY CRCW08051K00FKEA

1 RLIM 0.06 Ω1% 1 W VISHAY WSL2512R0600FEA

1 ROV2 499 kΩ1% VISHAY CRCW0805499KFKEA

1 RSNS 0.1 Ω1% 1 W VISHAY WSL2512R1000FEA

1 RT35.7 kΩ1% VISHAY CRCW080535K7FKEA

1 RUV1 1.82 kΩ1% VISHAY CRCW08051K82FKEA

1 RUV2 10 kΩ1% VISHAY CRCW080510KFKEA

1 RUVH 17.8 kΩ1% VISHAY CRCW080517K8FKEA

Product Folder Links: LM3429 LM3429-Q1

OVP

LM3429

nDIM

PGND

DAP

GATE

COMP

CSH

RCT

HSN

HSP

CIN

CBYP

RLIM

CCMP

RCSH

RUV2

RUV1

RHSN

RHSP

RSNS

AGND

RFS

CFS

RADJ

ILED

ROV2

ROV1

COV

VIN

10V ± 30V

VIN

VCC

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

8.2.4 Buck-Boost Analog Dimming Application - 4 LEDs at 2A

Figure 32. Buck-Boost Analog Dimming Application - 4 LEDs at 2 A Schematic

8.2.4.1 Detailed Design Procedure

Table 3. Bill of Materials

QTY PART ID PART VALUE MANUFACTURER PART NUMBER

1 LM3429 Boost controller TI LM3429MH

1 CCMP 1 µF X7R 10% 10 V MURATA GRM21BR71A105KA01L

1 CF2.2 µF X7R 10% 16 V MURATA GRM21BR71C225KA12L

1 CFS 0.1 µF X7R 10% 50 V MURATA GRM21BR71E104KA01L

2, 1 CIN, CO6.8 µF X7R 10% 50 V TDK C4532X7R1H685K

1 COV 47 pF COG/NPO 5% 50 V AVX 08055A470JAT2A

1 CT1000 pF COG/NPO 5% 50 V MURATA GRM2165C1H102JA01D

1 D1 Schottky 60 V 5 A VISHAY CDBC560-G

1 L1 22 µH 20% 7.2 A COILCRAFT MSS1278-223MLB

1 Q1 NMOS 60 V 8 A VISHAY SI4436DY

1 Q2 PNP 150 V 600 mA FAIRCHILD MMBT5401

1 RADJ 1-MΩpotentiometer BOURNS 3352P-1-105

1 RCSH 12.4 kΩ1% VISHAY CRCW080512K4FKEA

1 RFS 10 Ω1% VISHAY CRCW080510R0FKEA

2 RHSP, RHSN 1 kΩ1% VISHAY CRCW08051K00FKEA

1 RLIM 0.04 Ω1% 1 W VISHAY WSL2512R0400FEA

1 ROV1 18.2 kΩ1% VISHAY CRCW080518K2FKEA

1 ROV2 499 kΩ1% VISHAY CRCW0805499KFKEA

1 RSNS 0.05 Ω1% 1 W VISHAY WSL2512R0500FEA

1 RT41.2 kΩ1% VISHAY CRCW080541K2FKEA

Product Folder Links: LM3429 LM3429-Q1

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

Table 3. Bill of Materials (continued)

QTY PART ID PART VALUE MANUFACTURER PART NUMBER

1 RUV1 21 kΩ1% VISHAY CRCW080521K0FKEA

1 RUV2 150 kΩ1% VISHAY CRCW0805150KFKEA

Product Folder Links: LM3429 LM3429-Q1

700 mA

RSNS

OVP

LM3429

nDIM

PGND

DAP

GATE

COMP

CSH

RCT

HSN

HSP

CIN

CBYP

RLIM

CCMP

RUV2

RUV1

RHSN

RHSP

AGND

RFS

CFS

RBIAS

RMAX

VREF

RADJ

RCSH ILED

ROV1

ROV2

COV

VIN

18V - 38V

VIN

VCC

VIN

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

8.2.5 Boost Analog Dimming Application - 12 LEDs at 700 mA

Figure 33. Boost Analog Dimming Application - 12 LEDs at 700 mA Schematic

8.2.5.1 Detailed Design Procedure

Table 4. Bill of Materials

QTY PART ID PART VALUE MANUFACTURER PART NUMBER

1 LM3429 Boost controller TI LM3429MH

1 CCMP 1 µF X7R 10% 10 V MURATA GRM21BR71A105KA01L

1 CF2.2 µF X7R 10% 16 V MURATA GRM21BR71C225KA12L

1 CFS 0.1 µF X7R 10% 50 V MURATA GRM21BR71E104KA01L

2, 1 CIN, CO6.8 µF X7R 10% 50 V TDK C4532X7R1H685K

1 COV 47 pF COG/NPO 5% 50 V AVX 08055A470JAT2A

1 CT1000 pF COG/NPO 5% 50 V MURATA GRM2165C1H102JA01D

1 D1 Schottky 100 V 12 A VISHAY 12CWQ10FNPBF

1 L1 47 µH 20% 5.3 A COILCRAFT MSS1278-473MLB

1 Q1 NMOS 100 V 32 A FAIRCHILD FDD3682

1 Q2 NPN 40 V 200 mA FAIRCHILD MMBT3904

1 Q3, Q4 (dual pack) Dual PNP 40 V 200 mA FAIRCHILD FFB3906

1 RADJ 100 kΩpotentiometer BOURNS 3352P-1-104

1 RBIAS 40.2 kΩ1% VISHAY CRCW080540K2FKEA

1 RCSH, ROV1, RUV1 12.4 kΩ1% VISHAY CRCW080512K4FKEA

1 RFS 10 Ω1% VISHAY CRCW080510R0FKEA

2 RHSP, RHSN 1.05 kΩ1% VISHAY CRCW08051K05FKEA

1 RLIM 0.06 Ω1% 1 W VISHAY WSL2512R0600FEA

1 RMAX 4.99 kΩ1% VISHAY CRCW08054K99FKEA

1 ROV2 499 kΩ1% VISHAY CRCW0805499KFKEA

1 RSNS 0.15 Ω1% 1 W VISHAY WSL2512R1500FEA

Product Folder Links: LM3429 LM3429-Q1

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

Table 4. Bill of Materials (continued)

QTY PART ID PART VALUE MANUFACTURER PART NUMBER

1 RT35.7 kΩ1% VISHAY CRCW080535K7FKEA

1 RUV2 100 kΩ1% VISHAY CRCW0805100KFKEA

1 VREF 5 V precision reference TI LM4040

Product Folder Links: LM3429 LM3429-Q1

OVP

LM3429

nDIM

PGND

DAP

GATE

COMP

CSH

RCT

HSN

HSP

CIN

CBYP

CCMP

RCSH

RUV2

RUV1

RHSN

RHSP

500 mA

RSNS

AGND

RFS

CFS

ILED

ROV2

ROV1

COV

VIN

10V ± 70V

VIN

VCC

RUVH

PWM

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

8.2.6 Buck-Boost PWM Dimming Application - 6 LEDs at 500 mA

Figure 34. Buck-Boost PWM Dimming Application - 6 LEDs at 500 mA

8.2.6.1 Detailed Design Procedure

Table 5. Bill of Materials

QTY PART ID PART VALUE MANUFACTURER PART NUMBER

1 LM3429 Boost controller TI LM3429MH

1 CCMP 0.68 µF X7R 10% 25 V MURATA GRM21BR71E684KA88L

1 CF2.2 µF X7R 10% 16 V MURATA GRM21BR71C225KA12L

1 CFS 0.1 µF X7R 10% 25 V MURATA GRM21BR71E104KA01L

3 CIN 4.7 µF X7R 10% 100 V TDK C5750X7R2A475K

1 CO6.8 µF X7R 10% 50 V TDK C4532X7R1H685K

1 COV 47 pF COG/NPO 5% 50 V AVX 08055A470JAT2A

1 CT1000 pF COG/NPO 5% 50 V MURATA GRM2165C1H102JA01D

1 D1 Schottky 100 V 12 A VISHAY 12CWQ10FNPBF

1 D2 Schottky 30 V 500 mA ON SEMI BAT54T1G

1 L1 68 µH 20% 4.3 A COILCRAFT MSS1278-683MLB

1 Q1 NMOS 100 V 32 A VISHAY FDD3682

1 Q2 PNP 150 V 600 mA FAIRCHILD MMBT5401

1 RCSH 12.4 kΩ1% VISHAY CRCW080512K4FKEA

1 RFS 10 Ω1% VISHAY CRCW080510R0FKEA

2 RHSP, RHSN 1 kΩ1% VISHAY CRCW08051K00FKEA

1 ROV1 15.8 kΩ1% VISHAY CRCW080515K8FKEA

1 ROV2 499 kΩ1% VISHAY CRCW0805499KFKEA

1 RSNS 0.2 Ω1% 1 W VISHAY WSL2512R2000FEA

1 RT35.7 kΩ1% VISHAY CRCW080535K7FKEA

1 RUV1 1.43 kΩ1% VISHAY CRCW08051K43FKEA

1 RUV2 10 kΩ1% VISHAY CRCW080510K0FKEA

Product Folder Links: LM3429 LM3429-Q1

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

Table 5. Bill of Materials (continued)

QTY PART ID PART VALUE MANUFACTURER PART NUMBER

1 RUVH 17.4 kΩ1% VISHAY CRCW080517K4FKEA

Product Folder Links: LM3429 LM3429-Q1

OVP

LM3429

nDIM

VIN

PGND

DAP

GATE

COMP

CSH

RCT

HSN

HSP

CIN

CBYP

RLIM

CCMP

RCSH

RUV2

RUV1

RHSN

RHSP

ILED

ROV2

RSNS

AGND

RFS

CFS

VIN

ROV1

COV

VCC

1.25A

15V ± 50V

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

8.2.7 Buck Application - 3 LEDS at 1.25 A

Figure 35. Buck Application - 3 LEDS at 1.25 A Schematic

8.2.7.1 Detailed Design Procedure

Table 6. Bill of Materials

QTY PART ID PART VALUE MANUFACTURER PART NUMBER

1 LM3429 Boost controller TI LM3429MH

1 CCMP 0.015 µF X7R 10% 50 V MURATA GRM21BR71H153KA01L

1 CF2.2 µF X7R 10% 16 V MURATA GRM21BR71C225KA12L

1 CFS 0.01 µF X7R 10% 50 V MURATA GRM21BR71H103KA01L

2 CIN 6.8 µF X7R 10% 50 V TDK C4532X7R1H685K

1 CO1 µF X7R 10% 50 V TDK C4532X7R1H105K

1 COV 47 pF COG/NPO 5% 50 V AVX 08055A470JAT2A

1 CT1000 pF COG/NPO 5% 50 V MURATA GRM2165C1H102JA01D

1 D1 Schottky 60V 5 A COMCHIP CDBC560-G

1 L1 22 µH 20% 7.3 A COILCRAFT MSS1278-223MLB

1 Q1 NMOS 60 V 8 A VISHAY SI4436DY

1 Q2 PNP 150 V 600 mA FAIRCHILD MMBT5401

1 RCSH 12.4 kΩ1% VISHAY CRCW080512K4FKEA

1 RT49.9 kΩ1% VISHAY CRCW080549K9FKEA

1 RFS 10 Ω1% VISHAY CRCW080510R0FKEA

2 RHSP, RHSN 1 kΩ1% VISHAY CRCW08051K00FKEA

1 RLIM 0.04 Ω1% 1 W VISHAY WSL2512R0400FEA

1 ROV1 21.5 kΩ1% VISHAY CRCW080521K5FKEA

1 ROV2 499 kΩ1% VISHAY CRCW0805499KFKEA

1 RSNS 0.08 Ω1% 1 W VISHAY WSL2512R0800FEA

Product Folder Links: LM3429 LM3429-Q1

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

Table 6. Bill of Materials (continued)

QTY PART ID PART VALUE MANUFACTURER PART NUMBER

1 RUV1 11.5 kΩ1% VISHAY CRCW080511K5FKEA

1 RUV2 100 kΩ1% VISHAY CRCW0805100KFKEA

Product Folder Links: LM3429 LM3429-Q1

OVP

LM3429

nDIM

PGND

DAP

GATE

COMP

CSH

RCT

HSN

HSP

CIN

CBYP

CCMP

RCSH CT

RUV2

RUV1

RHSN

RHSP 2.5A

RSNS

AGND

RFS

CFS

ILED

ROV2

ROV1

COV

VIN

15V ± 60V

VIN

VCC

VREF

RBIAS D2

RNTC

RGAIN

VIN

RLIM

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

8.2.8 Buck-Boost Thermal Foldback Application - 8 LEDs at 2.5 A

Figure 36. Buck-Boost Thermal Foldback Application - 8 LEDs at 2.5 A Schematic

8.2.8.1 Detailed Design Procedure

Table 7. Bill of Materials

QTY PART ID PART VALUE MANUFACTURER PART NUMBER

1 LM3429 Boost controller TI LM3429MH

1 CCMP 0.1 µF X7R 10% 25 V MURATA GRM21BR71E104KA01L

1 CF2.2 µF X7R 10% 16 V MURATA GRM21BR71C225KA12L

1 CFS 0.1 µF X7R 10% 25 V MURATA GRM21BR71E104KA01L

3 CIN 4.7 µF X7R 10% 100 V TDK C5750X7R2A475K

1 CO6.8 µF X7R 10% 50 V TDK C4532X7R1H685K

1 COV 47 pF COG/NPO 5% 50 V AVX 08055A470JAT2A

1 CT1000 pF COG/NPO 5% 50 V MURATA GRM2165C1H102JA01D

1 D1 Schottky 100 V 12 A VISHAY 12CWQ10FNPBF

1 L1 22 µH 20% 7.2 A COILCRAFT MSS1278-223MLB

1 Q1 NMOS 100 V 32 A FAIRCHILD FDD3682

1 Q2 PNP 150 V 600 mA FAIRCHILD MMBT5401

2 RCSH, ROV1 12.4 kΩ1% VISHAY CRCW080512K4FKEA

1 RFS 10 Ω1% VISHAY CRCW080510R0FKEA

2 RHSP, RHSN 1 kΩ1% VISHAY CRCW08051K00FKEA

2 RLIM, RSNS 0.04 Ω1% 1 W VISHAY WSL2512R0400FEA

1 ROV2 499 kΩ1% VISHAY CRCW0805499KFKEA

1 RT49.9 kΩ1% VISHAY CRCW080549K9FKEA

1 RUV1 13.7 kΩ1% VISHAY CRCW080513K7FKEA

1 RUV2 150 kΩ1% VISHAY CRCW0805150KFKEA

Product Folder Links: LM3429 LM3429-Q1

OVP

LM3429

nDIM

VIN

PGND

DAP

GATE

COMP

CSH

RCT

HSN

HSP

CIN

CBYP

CCMP

RCSH

RUV2

RUV1

RHSN

RHSP

AGND

RSNS

RFS

CFS

ILED

ROV1

ROV2

COV

VIN

9V - 36V

750 mA

VCC

CSEP

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

8.2.9 SEPIC Application - 5 LEDs at 750 mA

Figure 37. 5 LEDs at 750 mA

8.2.9.1 Detailed Design Procedure

Table 8. Bill of Materials

QTY PART ID PART VALUE MANUFACTURER PART NUMBER

1 LM3429 Boost controller TI LM3429MH

1 CCMP 0.47 µF X7R 10% 25 V MURATA GRM21BR71E474KA01L

1 CF2.2 µF X7R 10% 16 V MURATA GRM21BR71C225KA12L

1 CFS 0.1 µF X7R 10% 25 V MURATA GRM21BR71E104KA01L

2, 1 CIN, CO6.8 µF X7R 10% 50 V TDK C4532X7R1H685K

1 COV 47 pF COG/NPO 5% 50 V AVX 08055A470JAT2A

1 CSEP 1 µF X7R 10% 100 V TDK C4532X7R2A105K

1 CT1000 pF COG/NPO 5% 50 V MURATA GRM2165C1H102JA01D

1 D1 Schottky 60 V 5 A COMCHIP CDBC560-G

1 L1, L2 68 µH 20% 4.3 A COILCRAFT DO3340P-683

1 Q1 NMOS 60 V 8 A VISHAY SI4436DY

1 Q2 NMOS 60 V 115 mA ON SEMI 2N7002ET1G

1 RCSH 12.4 kΩ1% VISHAY CRCW080512K4FKEA

1 RFS 10 Ω1% VISHAY CRCW080510R0FKEA

2 RHSP, RHSN 750 Ω1% VISHAY CRCW0805750RFKEA

1 RLIM 0.04 Ω1% 1 W VISHAY WSL2512R0400FEA

2 ROV1, RUV1 15.8 kΩ1% VISHAY CRCW080515K8FKEA

1 ROV2 499 kΩ1% VISHAY CRCW0805499KFKEA

1 RSNS 0.1 Ω1% 1 W VISHAY WSL2512R1000FEA

1 RT49.9 kΩ1% VISHAY CRCW080549K9FKEA

Product Folder Links: LM3429 LM3429-Q1

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

Table 8. Bill of Materials (continued)

QTY PART ID PART VALUE MANUFACTURER PART NUMBER

1 RUV2 100 kΩ1% VISHAY CRCW0805100KFKEA

Product Folder Links: LM3429 LM3429-Q1

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

9 Power Supply Recommendations

The device is designed to operate from an input voltage supply range from 4.5 V to 75 V. This input supply

should be well regulated. If the input supply is located more than a few inches from the EVM or PCB, additional

bulk capacitance may be required in addition to the ceramic bypass capacitors.

9.1 Input Supply Current Limit

It is important to set the output current limit of your input supply to an appropriate value to avoid delays in your

converter analysis and optimization. If not set high enough, current limit can be tripped during start-up or when

your converter output power is increased, causing a foldback or shut-down condition. It is a common oversight

when powering up a converter for the first time.

10 Layout

10.1 Layout Guidelines

The performance of any switching regulator depends as much upon the layout of the PCB as the component

selection. Following a few simple guidelines will maximimize noise rejection and minimize the generation of EMI

within the circuit.

Discontinuous currents are the most likely to generate EMI; therefore, take care when routing these paths. The

main path for discontinuous current in the LM3429 buck regulator contains the input capacitor (CIN), the

recirculating diode (D1), the N-channel MosFET (Q1), and the switch sense resistor (RLIM). In the LM3429 boost

and buck-boost regulators, the discontinuous current flows through the output capacitor (CO), D1, Q1, and RLIM.

In either case, this loop should be kept as small as possible and the connections between all the components

should be short and thick to minimize parasitic inductance. In particular, the switch node (where L1, D1 and Q1

connect) should be just large enough to connect the components. To minimize excessive heating, large copper

pours can be placed adjacent to the short current path of the switch node.

The RCT, COMP, CSH, IS, HSP and HSN pins are all high-impedance inputs which couple external noise easily,

therefore the loops containing these nodes should be minimized whenever possible.

In some applications the LED or LED array can be far away (several inches or more) from the LM3429, or on a

separate PCB connected by a wiring harness. When an output capacitor is used and the LED array is large or

separated from the rest of the regulator, the output capacitor should be placed close to the LEDs to reduce the

effects of parasitic inductance on the AC impedance of the capacitor.

Product Folder Links: LM3429 LM3429-Q1

Note critical paths and component placement:

Minimize power loop containing discontinuous currents

Minimize signal current loops (components close to IC)

x Ground plane under IC for signal routing helps minimize noise coupling

ILED

ROV1

ROV2

RSNS

OVP

LM3429

nDIM

VIN

PGND

DAP

GATE

COMP

CSH

RCT

HSN

HSP

CIN

CBYP

RLIM

CCMP

RCSH

RUV2

RUV1

RHSN

RHSP

AGND

RUVH

PWM

RFS

CFS

COV

VIN

VCC

Input

Power

GND

STAR GROUND

Power Ground

discontinuous switching

frequency currents

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

10.2 Layout Example

Figure 38. LM3429 Layout Guideline

Product Folder Links: LM3429 LM3429-Q1

LM3429

LM3429-Q1

www.ti.com

SNVS616H –APRIL 2009–REVISED JULY 2015

11 Device and Documentation Support

11.1 Device Support

11.1.1 Third-Party Products Disclaimer

TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT

CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES

OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER

ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE.

11.2 Documentation Support

11.2.1 Related Documentation

For related documentation see the following:

•AN-1986 LM3429 Boost Evaluation Board,SNVA404

•AN-1985 LM3429 Buck-Boost Evaluation Board,SNVA403

11.3 Related Links

The table below lists quick access links. Categories include technical documents, support and community

resources, tools and software, and quick access to sample or buy.

Table 9. Related Links

TECHNICAL TOOLS & SUPPORT &

PARTS PRODUCT FOLDER SAMPLE & BUY DOCUMENTS SOFTWARE COMMUNITY

LM3429 Click here Click here Click here Click here Click here

LM3429-Q1 Click here Click here Click here Click here Click here

11.4 Community Resources

The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective

contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of

Use.

TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration

among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help

solve problems with fellow engineers.

Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and

contact information for technical support.

The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective

contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of

Use.

TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration

among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help

solve problems with fellow engineers.

Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and

contact information for technical support.

11.5 Trademarks

E2E is a trademark of Texas Instruments.

All other trademarks are the property of their respective owners.

Product Folder Links: LM3429 LM3429-Q1

LM3429

LM3429-Q1

SNVS616H –APRIL 2009–REVISED JULY 2015

www.ti.com

11.6 Electrostatic Discharge Caution

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

11.7 Glossary

SLYZ022 —TI Glossary.

This glossary lists and explains terms, acronyms, and definitions.

12 Mechanical, Packaging, and Orderable Information

The following pages include mechanical, packaging, and orderable information. This information is the most

current data available for the designated devices. This data is subject to change without notice and revision of

this document. For browser-based versions of this data sheet, refer to the left-hand navigation.

Product Folder Links: LM3429 LM3429-Q1

PACKAGE OPTION ADDENDUM

www.ti.com 6-Feb-2020

Addendum-Page 1

PACKAGING INFORMATION

Orderable Device Status

(1)

Package Type Package

Drawing Pins Package

Qty Eco Plan

(2)

Lead/Ball Finish

(6)

MSL Peak Temp

(3)

Op Temp (°C) Device Marking

(4/5)

Samples

LM3429MH/NOPB ACTIVE HTSSOP PWP 14 94 Green (RoHS

& no Sb/Br) SN Level-1-260C-UNLIM -40 to 125 LM3429

LM3429MHX/NOPB ACTIVE HTSSOP PWP 14 2500 Green (RoHS

& no Sb/Br) SN Level-1-260C-UNLIM -40 to 125 LM3429

LM3429Q1MH/NOPB ACTIVE HTSSOP PWP 14 94 Green (RoHS

& no Sb/Br) SN Level-1-260C-UNLIM -40 to 125 LM3429

Q1MH

LM3429Q1MHX/NOPB ACTIVE HTSSOP PWP 14 2500 Green (RoHS

& no Sb/Br) SN Level-1-260C-UNLIM -40 to 125 LM3429

Q1MH

(1) The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs.

LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.

NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available.

OBSOLETE: TI has discontinued the production of the device.

(2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance

do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may

reference these types of products as "Pb-Free".

RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.

Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based

flame retardants must also meet the <=1000ppm threshold requirement.

(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.

(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.

(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation

of the previous line and the two combined represent the entire Device Marking for that device.

(6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish

value exceeds the maximum column width.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information

provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and

PACKAGE OPTION ADDENDUM

www.ti.com 6-Feb-2020

Addendum-Page 2

continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.

TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.

In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

OTHER QUALIFIED VERSIONS OF LM3429, LM3429-Q1 :

•Catalog: LM3429

•Automotive: LM3429-Q1

NOTE: Qualified Version Definitions:

•Catalog - TI's standard catalog product

•Automotive - Q100 devices qualified for high-reliability automotive applications targeting zero defects

TAPE AND REEL INFORMATION

*All dimensions are nominal

Device Package

Type Package

Drawing Pins SPQ Reel

Diameter

(mm)

Reel

Width

W1 (mm)

(mm) B0

(mm) K0

(mm) P1

(mm) W

(mm) Pin1

Quadrant

LM3429MHX/NOPB HTSSOP PWP 14 2500 330.0 12.4 6.95 5.6 1.6 8.0 12.0 Q1

LM3429Q1MHX/NOPB HTSSOP PWP 14 2500 330.0 12.4 6.95 5.6 1.6 8.0 12.0 Q1

PACKAGE MATERIALS INFORMATION

www.ti.com 6-Nov-2015

Pack Materials-Page 1

*All dimensions are nominal

Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)

LM3429MHX/NOPB HTSSOP PWP 14 2500 367.0 367.0 35.0

LM3429Q1MHX/NOPB HTSSOP PWP 14 2500 367.0 367.0 35.0

PACKAGE MATERIALS INFORMATION

www.ti.com 6-Nov-2015

Pack Materials-Page 2

MECHANICAL DATA

PWP0014A

www.ti.com

MXA14A (Rev A)

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