LM22677TJE-ADJ/NOPB - NATIONAL SEMICONDUCTOR

LM22677-ADJ

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VIN

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RT/SYNC

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LM22677

LM22677-Q1

SNVS582O –SEPTEMBER 2008–REVISED AUGUST 2015

LM22677/-Q1 42-V, 5-A SIMPLE SWITCHER

, Step-Down Voltage Regulator

With Features

1 Features 3 Description

The LM22677 switching regulator provides all of the

1• Wide Input Voltage Range: 4.5 V to 42 V functions necessary to implement an efficient high-

• Internally Compensated Voltage Mode Control voltage step-down (buck) regulator using a minimum

• Stable With Low ESR Ceramic Capacitors of external components. This easy-to-use regulator

incorporates a 42-V N-channel MOSFET switch that

• 100-mΩN-Channel MOSFET can provide up to 5 A of load current. Excellent line

• Output Voltage Options: and load regulation along with high efficiency (> 90%)

– -ADJ (Outputs as Low as 1.285 V) are featured. Voltage mode control offers short

minimum on-time, allowing the widest ratio between

– -5.0 (Output Fixed to 5 V) input and output voltages. Internal loop compensation

• ±1.5% Feedback Reference Accuracy means that the user is free from the tedious task of

• 500-kHz Default Switching Frequency calculating the loop compensation components. Fixed

• Adjustable Switching Frequency and 5-V output and adjustable output voltage options are

available. The default switching frequency is set at

Synchronization 500 kHz, thus allowing for small external components

• –40°C to +125°C Operating Junction Temperature and good transient response. In addition, the

Range frequency can be adjusted over a range of 200 kHz

• Precision Enable Input to 1 MHz with a single external resistor. The internal

• Integrated Boot-Strap Diode oscillator can be synchronized to a system clock or to

the oscillator of another regulator. A precision enable

• Integrated Soft-Start input allows simplification of regulator control and

• Fully WEBENCH®Enabled system power sequencing. In shutdown mode the

• LM22677-Q1 is an Automotive-Grade Product regulator draws only 25 µA (typical). The LM22677

that is AEC-Q100 Grade 1 Qualified (–40°C to also has built-in thermal shutdown, and current

limiting to protect against accidental overloads.

+125°C Operating Junction Temperature)

• NDR (Exposed Pad) The LM22677 device is a member of Texas

Instruments' SIMPLE SWITCHER®family. The

2 Applications SIMPLE SWITCHER concept provides for an easy-to-

use complete design using a minimum number of

• Industrial Control external components and the TI WEBENCH design

• Telecom and Datacom Systems tool. TI's WEBENCH tool includes features such as

external component calculation, electrical simulation,

• Embedded Systems thermal simulation, and Build-It boards for easy

• Conversions from Standard 24-V, 12-V and 5-V design-in.

Input Rails

Device Information(1)

Simplified Application Schematic PART NUMBER PACKAGE BODY SIZE (NOM)

LM22677 TO-263 (7) 10.16 mm x 9.85 mm

LM22677-Q1

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

the end of the data sheet.

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.

LM22677

LM22677-Q1

SNVS582O –SEPTEMBER 2008–REVISED AUGUST 2015

www.ti.com

Table of Contents

7.4 Device Functional Modes........................................ 12

1 Features.................................................................. 18 Applications and Implementation ...................... 15

2 Applications ........................................................... 18.1 Application Information............................................ 15

3 Description............................................................. 18.2 Typical Application.................................................. 16

4 Revision History..................................................... 29 Power Supply Recommendations...................... 19

5 Pin Configuration and Functions......................... 310 Layout................................................................... 19

6 Specifications......................................................... 410.1 Layout Guidelines ................................................. 19

6.1 Absolute Maximum Ratings ...................................... 410.2 Layout Example .................................................... 20

6.2 ESD Ratings: LM22677 ............................................ 410.3 Thermal Considerations........................................ 21

6.3 ESD Ratings: LM22677-Q1 ...................................... 411 Device and Documentation Support................. 22

6.4 Recommended Operating Conditions....................... 411.1 Documentation Support ........................................ 22

6.5 Thermal Information.................................................. 411.2 Related Links ........................................................ 22

6.6 Electrical Characteristics........................................... 511.3 Trademarks........................................................... 22

6.7 Typical Characteristics.............................................. 611.4 Electrostatic Discharge Caution............................ 22

7 Detailed Description.............................................. 811.5 Glossary................................................................ 22

7.1 Overview................................................................... 812 Mechanical, Packaging, and Orderable

7.2 Functional Block Diagram......................................... 8Information........................................................... 22

7.3 Feature Description................................................... 8

4 Revision History

Changes from Revision N (November 2014) to Revision O Page

• Changed the word Pin to Input............................................................................................................................................... 1

• Changed the Q grade part number corrected to LM22677 from LM2677'; added icon for Reference Design to top navs ... 1

• Changed "PFM" Package to "NDR" Package ....................................................................................................................... 3

Changes from Revision M (April 2013) to Revision N 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

• Deleted Inverting Regulator Application............................................................................................................................... 15

Product Folder Links: LM22677 LM22677-Q1

Exposed Pad

Connect to GND

5 RT/SYNC

6 FB

3 BOOT

1 SW

2 VIN

4 GND

7 EN

LM22677

LM22677-Q1

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SNVS582O –SEPTEMBER 2008–REVISED AUGUST 2015

5 Pin Configuration and Functions

NDR Package

7-Pin TO-263

Top View

Pin Functions

PIN TYPE(1) DESCRIPTION APPLICATION INFORMATION

NAME NO.

SW 1 O Switch output Switching output of regulator

VIN 2 I Input voltage Supply input to the regulator

BOOT 3 I Bootstrap input Provides the gate voltage for the high side N-FET

Ground input to

GND 4 — regulator; system System ground pin

common

Oscillator mode control Used to control oscillator mode of regulator. See Switching Frequency

RT/SYNC 5 I input Adjustment and Synchronization section of data sheet.

FB 6 I Feedback input Feedback input to regulator

Used to control regulator start-up and shutdown. See Precision Enable

EN 7 I Enable input and UVLO section of data sheet.

Connect to ground. Provides thermal connection to PCB. See

EP EP — Exposed Pad Applications and Implementation.

(1) O = Output, I = Input, G = Ground, P = Power

Product Folder Links: LM22677 LM22677-Q1

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6 Specifications

6.1 Absolute Maximum Ratings(1)(2)

MIN MAX UNIT

VIN to GND 43 V

EN Pin Voltage –0.5 6 V

RT/SYNC Pin Voltage –0.5 7 V

SW to GND(3) –5 VIN V

BOOT Pin Voltage VSW + 7 V

FB Pin Voltage –0.5 7 V

Power Dissipation Internally Limited

Junction Temperature 150 °C

For soldering specifications, refer to Application Report Absolute Maximum Ratings for Soldering (SNOA549).

Storage temperature, Tstg –65 150 °C

(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur, including inoperability and degradation of

device reliability and/or performance. Functional operation of the device and/or non-degradation at the absolute maximum ratings or

other conditions beyond those indicated in the Recommended Operating Conditions is not implied. The Recommended Operating

Conditions indicate conditions at which the device is functional and should not be operated beyond such conditions.

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

specifications.

(3) The absolute-maximum specification of the ‘SW to GND’ applies to dc voltage. An extended negative voltage limit of –10 V applies to a

pulse of up to 50 ns.

6.2 ESD Ratings: LM22677 VALUE UNIT

V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 V

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

6.3 ESD Ratings: LM22677-Q1 VALUE UNIT

V(ESD) Electrostatic discharge Human-body model (HBM), per AEC Q100-002(1) ±2000 V

(1) AEC Q100-002 indicates that HBM stressing shall be in accordance with the ANSI/ESDA/JEDEC JS-001 specification.

6.4 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted) MIN MAX UNIT

VIN Supply Voltage 4.5 42 V

Junction Temperature –40 125 °C

6.5 Thermal Information LM22677

THERMAL METRIC(1)(2) NDR (TO-263) UNIT

7 PINS

RθJA Junction-to-ambient thermal resistance 22 °C/W

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

report (SPRA953).

(2) The value of RθJA for the NDR (TJ) package of 22°C/W is valid if package is mounted to 1 square inch of copper. The RθJA value can

range from 20 to 30°C/W depending on the amount of PCB copper dedicated to heat transfer. See application note AN-1797 TO-263

THIN Package (SNVA328) for more information.

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6.6 Electrical Characteristics

Typical values represent the most likely parametric norm at TA= TJ= 25°C, and are provided for reference purposes only.

Unless otherwise specified: VIN = 12 V.

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

LM22677-5.0

VIN = 8 V to 42 V 4.925 5.0 5.075

VFB Feedback Voltage V

VIN = 8 V to 42 V, –40°C ≤TJ≤125°C 4.9 5.1

LM22677-ADJ

VIN = 4.7 V to 42 V 1.266 1.285 1.304

VFB Feedback Voltage V

VIN = 4.7 V to 42 V, –40°C ≤TJ≤125°C 1.259 1.311

ALL OUTPUT VOLTAGE VERSIONS

VFB = 5 V 3.4

IQQuiescent Current mA

VFB = 5 V, –40°C ≤TJ≤125°C 6

ISTDBY Standby Quiescent Current EN Pin = 0 V 25 40 µA

6.0 7.1 8.4

ICL Current Limit A

–40°C ≤TJ≤125°C 5.75 8.75

VIN = 42 V, EN Pin = 0 V, VSW = 0 V 0.2 2 µA

ILOutput Leakage Current VSW = –1 V 0.1 3 µA

0.1 0.14

RDS(ON) Switch On-Resistance Ω

–40°C ≤TJ≤125°C 0.2

500

fOOscillator Frequency kHz

–40°C ≤TJ≤125°C 400 600

200

TOFFMIN Minimum Off-time ns

–40°C ≤TJ≤125°C 100 300

TONMIN Minimum On-time 100 ns

IBIAS Feedback Bias Current VFB = 1.3 V (ADJ Version Only) 230 nA

Falling 1.6

VEN Enable Threshold Voltage V

Falling, –40°C ≤TJ≤125°C 1.3 1.9

VENHYST Enable Voltage Hysteresis 0.6 V

IEN Enable Input Current EN Input = 0 V 6 µA

FSYNC Maximum Synchronization Frequency VSYNC = 3.5 V, 50% duty-cycle 1 MHz

VSYNC Synchronization Threshold Voltage 1.75 V

TSD Thermal Shutdown Threshold 150 °C

(1) MIN and MAX limits are 100% production tested at 25°C. Limits over the operating temperature range are ensured through correlation

using Statistical Quality Control (SQC) methods. Limits are used to calculate TI's Average Outgoing Quality Level (AOQL).

(2) Typical values represent most likely parametric norms at the conditions specified and are not ensured.

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6.7 Typical Characteristics

VIN = 12 V, TJ= 25°C (unless otherwise specified).

Figure 2. Normalized Switching Frequency vs Temperature

Figure 1. Efficiency vs IOUT and VIN, VOUT = 3.3 V

Figure 4. Normalized RDS(ON) vs Temperature

Figure 3. Current Limit vs Temperature

Figure 5. Feedback Bias Current vs Temperature Figure 6. Normalized Enable Threshold Voltage vs

Temperature

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Typical Characteristics (continued)

VIN = 12 V, TJ= 25°C (unless otherwise specified).

Figure 8. Normalized Feedback Voltage vs Temperature

Figure 7. Standby Quiescent Current vs Input Voltage

Figure 10. Switching Frequency vs RT/SYNC Resistor

Figure 9. Normalized Feedback Voltage vs Input Voltage

Product Folder Links: LM22677 LM22677-Q1

LOGIC

OSC

TYPE III

COMP

1.285V

Soft-Start

INT REG, EN,UVLO

GNDRT/SYNC

BOOT

VIN

VOUT

Error Amp.

PWM Cmp.

Vcc

ILimit

LM22677

LM22677-Q1

SNVS582O –SEPTEMBER 2008–REVISED AUGUST 2015

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7 Detailed Description

7.1 Overview

The LM22677 device incorporates a voltage mode constant frequency PWM architecture. In addition, input

voltage feedforward is used to stabilize the loop gain against variations in input voltage. This allows the loop

compensation to be optimized for transient performance. The power MOSFET, in conjunction with the diode,

produce a rectangular waveform at the switch pin, that swings from about zero volts to VIN. The inductor and

output capacitor average this waveform to become the regulator output voltage. By adjusting the duty cycle of

this waveform, the output voltage can be controlled. The error amplifier compares the output voltage with the

internal reference and adjusts the duty cycle to regulate the output at the desired value.

The internal loop compensation of the -ADJ option is optimized for outputs of 5 V and below. If an output voltage

of 5 V or greater is required, the -5.0 option can be used with an external voltage divider. The minimum output

voltage is equal to the reference voltage, that is, 1.285 V (typical).

7.2 Functional Block Diagram

7.3 Feature Description

7.3.1 Precision Enable and UVLO

The precision enable input (EN) is used to control the regulator. The precision feature allows simple sequencing

of multiple power supplies with a resistor divider from another supply. Connecting this pin to ground or to a

voltage less than 1.6 V (typical) will turn off the regulator. The current drain from the input supply, in this state, is

25 µA (typical) at an input voltage of 12 V. The EN input has an internal pullup of about 6 µA. Therefore this pin

can be left floating or pulled to a voltage greater than 2.2 V (typical) to turn the regulator on. The hysteresis on

this input is about 0.6 V (typical) above the 1.6 V (typical) threshold. When driving the enable input, the voltage

must never exceed the 6 V absolute maximum specification for this pin.

Product Folder Links: LM22677 LM22677-Q1

Vin

RENB

RENT

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SNVS582O –SEPTEMBER 2008–REVISED AUGUST 2015

Feature Description (continued)

Although an internal pullup is provided on the EN pin, it is good practice to pull the input high, when this feature

is not used, especially in noisy environments. This can most easily be done by connecting a resistor between VIN

and the EN pin. The resistor is required, because the internal zener diode, at the EN pin, will conduct for

voltages above about 6 V. The current in this zener must be limited to less than 100 µA. A resistor of 470 kΩwill

limit the current to a safe value for input voltages as high 42 V. Smaller values of resistor can be used at lower

input voltages.

The LM22677 also incorporates an input undervoltage lock-out (UVLO) feature. This prevents the regulator from

turning on when the input voltage is not great enough to properly bias the internal circuitry. The rising threshold is

4.3 V (typical) while the falling threshold is 3.9 V (typical). In some cases these thresholds may be too low to

provide good system performance. The solution is to use the EN input as an external UVLO to disable the part

when the input voltage falls below a lower boundary. This is often used to prevent excessive battery discharge or

early turn-on during start-up. This method is also recommended to prevent abnormal device operation in

applications where the input voltage falls below the minimum of 4.5 V. Figure 11 shows the connections to

implement this method of UVLO. Equation 1 and Equation 2 can be used to determine the correct resistor

values.

(1)

where

• Voff is the input voltage where the regulator shuts off.

• Von is the voltage where the regulator turns on. (2)

Due to the 6 µA pullup, the current in the divider should be much larger than this. A value of 20 kΩ, for RENB is a

good first choice. Also, a zener diode may be needed between the EN pin and ground, in order to comply with

the absolute maximum ratings on this pin.

Figure 11. External UVLO Connections

7.3.2 Soft-Start

The soft-start feature allows the regulator to gradually reach steady-state operation, thus reducing start-up

stresses. The internal soft-start feature brings the output voltage up in about 500 µs. This time is fixed and can

not be changed. Soft-start is reset any time the part is shut down or a thermal overload event occurs.

7.3.3 Switching Frequency Adjustment and Synchronization

The LM22677 will operate in three different modes, depending on the condition of the RT/SYNC pin. With the

RT/SYNC pin floating, the regulator will switch at the internally set frequency of 500 kHz (typ). With a resistor in

the range of 25 kΩto 200 kΩ, connected from RT/SYNC to ground, the internal switching frequency can be

adjusted from 1 MHz to 200 kHz. Figure 12 shows the typical curve for switching frequency versus the external

resistance connected to the RT/SYNC pin. The accuracy of the switching frequency, in this mode, is slightly

worse than that of the internal oscillator; about ±25% is to be expected. Finally, an external clock can be applied

to the RT/SYNC pin to allow the regulator to synchronize to a system clock or another LM22677. The mode is

set during start-up of the regulator. When the LM22677 is enabled, or after VIN is applied, a weak pullup is

connected to the RT/SYNC pin and, after approximately 100 µs, the voltage on the pin is checked against a

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Feature Description (continued)

threshold of about 0.8 V. With the RT/SYNC pin open, the voltage floats above this threshold, and the mode is

set to run with the internal clock. With a frequency set resistor present, an internal reference holds the pin

voltage at 0.8 V; the resulting current sets the mode to allow the resistor to control the clock frequency. If the

external circuit forces the RT/SYNC pin to a voltage much greater or less than 0.8 V, the mode is set to allow

external synchronization. The mode is latched until either the EN or the input supply is cycled.

The choice of switching frequency is governed by several considerations. As an example, lower frequencies may

be desirable to reduce switching losses or improve duty cycle limits. Higher frequencies, or a specific frequency,

may be desirable to avoid problems with EMI or reduce the physical size of external components. The flexibility

of increasing the switching frequency above 500 kHz can also be used to operate outside a critical signal

frequency band for a given application. Keep in mind that the values of inductor and output capacitor cannot be

reduced dramatically, by operating above 500 kHz. This is true because the design of the internal loop

compensation restricts the range of these components.

Frequency synchronization requires some care. First the external clock frequency must be greater than the

internal clock frequency, and less than 1 MHz. The maximum internal switching frequency is specified in the

Electrical Characteristics table.

NOTE

The frequency adjust feature and the synchronization feature can not be used

simultaneously.

The synchronizing frequency must always be greater than the internal clock frequency. Secondly, the RT/SYNC

pin must see a valid high or low voltage, during start-up, in order for the regulator to go into the synchronizing

mode (see above). Also, the amplitude of the synchronizing pulses must comport with VSYNC levels found in the

Electrical Characteristics table. The regulator will synchronize on the rising edge of the external clock. If the

external clock is lost during normal operation, the regulator will revert to the 500 kHz (typical) internal clock.

If the frequency synchronization feature is used, current limit foldback is not operational (see the Current Limit

section for details).

Figure 12. Switching Frequency vs RT/SYNC Resistor

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LM22677 LM22677

RT/SYNC

Vout

1 k

2N7002

ENABLE

1 k

RT/SYNC

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Feature Description (continued)

7.3.4 Self Synchronization

It is possible to synchronize multiple LM22677 regulators together to share the same switching frequency. This

can be done by tying the RT/SYNC pins together through a MOSFET and connecting a 1 kΩresistor to ground

at each pin. Figure 13 shows this connection. The gate of the MOSFET should be connected to the regulator

with the highest output voltage. Also, the EN pins of both regulators should be tied to the common system

enable, in order to properly initialize both regulators. The operation is as follows: When the regulators are

enabled, the outputs are low and the MOSFET is off. The 1 kΩresistors pull the RT/SYNC pins low, thus

enabling the synchronization mode. These resistors are small enough to pull the RT/SYNC pin low, rather than

activate the frequency adjust mode. Once the output voltage of one of the regulators is sufficient to turn on the

MOSFET, the two RT/SYNC pins are tied together and the regulators will run in synchronization mode. The two

regulators will be clocked at the same frequency but slightly phase shifted according to the minimum off-time of

the regulator with the fastest internal oscillator. The slight phase shift helps to reduce stress on the input

capacitors of the regulator. It is important to choose a MOSFET with a low gate threshold voltage so that the

MOSFET will be fully enhanced. Also, a MOSFET with low inter-electrode capacitance is required. The 2N7002

is a good choice.

Figure 13. Self Synchronizing Setup

7.3.5 Boot-Strap Supply

The LM22677 incorporates a floating high-side gate driver to control the power MOSFET. The supply for this

driver is the external boot-strap capacitor connected between the BOOT pin and SW. A good quality 10 nF

ceramic capacitor must be connected to these pins with short, wide PCB traces. One reason the regulator

imposes a minimum off-time is to ensure that this capacitor recharges every switching cycle. A minimum load of

about 5 mA is required to fully recharge the boot-strap capacitor in the minimum off-time. Some of this load can

be provided by the output voltage divider, if used.

7.3.6 Internal Compensation

The LM22677 has internal loop compensation designed to provide a stable regulator over a wide range of

external power stage components. The internal compensation of the -ADJ option is optimized for output voltages

below 5 V. If an output voltage of 5 V or greater is needed, the -5.0 option with an external resistor divider can be

used.

Ensuring stability of a design with a specific power stage (inductor and output capacitor) can be tricky. The

LM22677 stability can be verified using the WEBENCH Designer online circuit simulation tool. A quick start

spreadsheet can also be downloaded from the online product folder.

The complete transfer function for the regulator loop is found by combining the compensation and power stage

transfer functions. The LM22677 has internal type III loop compensation, as detailed in Figure 14. This is the

approximate "straight line" function from the FB pin to the input of the PWM modulator. The power stage transfer

function consists of a dc gain and a second order pole created by the inductor and output capacitor(s). Due to

the input voltage feedforward employed in the LM22677, the power stage dc gain is fixed at 20 dB. The second

order pole is characterized by its resonant frequency and its quality factor (Q). For a first pass design, the

product of inductance and output capacitance should conform to Equation 3.

(3)

Product Folder Links: LM22677 LM22677-Q1

100 1k 10k 100k 1M 10M

COMPENSATOR GAIN (dB)

FREQUENCY (Hz)

-ADJ

-5.0

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Feature Description (continued)

Alternatively, this pole should be placed between 1.5 kHz and 15 kHz and is given by Equation 4.

(4)

The Q factor depends on the parasitic resistance of the power stage components and is not typically in the

control of the designer. Of course, loop compensation is only one consideration when selecting power stage

components (see the Applications and Implementation section for more details).

Figure 14. Compensator Gain

In general, hand calculations or simulations can only aid in selecting good power stage components. Good

design practice dictates that load and line transient testing should be done to verify the stability of the application.

Also, Bode plot measurements should be made to determine stability margins. AN-1889 How to Measure the

Loop Transfer Function of Power Supplies (SNVA364) shows how to perform a loop transfer function

measurement with only an oscilloscope and function generator.

7.4 Device Functional Modes

7.4.1 Current Limit

The LM22677 has current limiting to prevent the switch current from exceeding safe values during an accidental

overload on the output. This peak current limit is found in the Electrical Characteristics table under the heading of

ICL. The maximum load current that can be provided, before current limit is reached, is determined from

Equation 5.

where

• L is the value of the power inductor. (5)

When the LM22677 enters current limit, the output voltage will drop and the peak inductor current will be fixed at

ICL at the end of each cycle. The switching frequency will remain constant while the duty cycle drops. The load

current will not remain constant, but will depend on the severity of the overload and the output voltage.

For very severe overloads ("short-circuit"), the regulator changes to a low frequency current foldback mode of

operation. The frequency foldback is about 1/5 of the nominal switching frequency. This will occur when the

current limit trips before the minimum on-time has elapsed. This mode of operation is used to prevent inductor

current "run-away", and is associated with very low output voltages when in overload. Equation 6 can be used to

determine what level of output voltage will cause the part to change to low frequency current foldback.

Product Folder Links: LM22677 LM22677-Q1

0.0 0.2 0.4 0.6 0.8 1.0 1.2

INPUT VOLTAGE (v)

SHORT CIRCUIT VOLTAGE (v)

SAFE OPERATING AREA

0.0 0.2 0.4 0.6 0.8 1.0 1.2

INPUT VOLTAGE (v)

SHORT CIRCUIT VOLTAGE (v)

SAFE OPERATING AREA

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SNVS582O –SEPTEMBER 2008–REVISED AUGUST 2015

Device Functional Modes (continued)

where

• Fsw is the normal switching frequency.

• Vin is the maximum for the application. (6)

If the overload drives the output voltage to less than or equal to Vx, the device will enter current foldback mode. If

a given application can drive the output voltage to ≤Vx, during an overload, then a second criterion must be

checked. Equation 7 gives the maximum input voltage, when in this mode, before damage occurs:

where

• Vsc is the value of output voltage during the overload.

• Fsw is the normal switching frequency. (7)

NOTE

If the input voltage should exceed this value while in foldback mode, the regulator and/or

the diode may be damaged.

It is important to note that the voltages in these equations are measured at the inductor. Normal trace and wiring

resistance will cause the voltage at the inductor to be higher than that at a remote load. Therefore, even if the

load is shorted with zero volts across its terminals, the inductor will still see a finite voltage. It is this value that

should be used for Vxand Vsc in the calculations. In order to return from foldback mode, the load must be

reduced to a value much lower than that required to initiate foldback. This load "hysteresis" is a normal aspect of

any type of current limit foldback associated with voltage regulators.

If the frequency synchronization feature is used, the current limit frequency fold-back is not operational, and the

system may not survive a hard short-circuit at the output.

The safe operating areas, when in short circuit mode, are shown in Figure 15 through Figure 17, for different

switching frequencies. Operating points below and to the right of the curve represent safe operation.

NOTE

Figure 15,Figure 16, and Figure 17 curves are not valid when the LM22677 is in

frequency synchronization mode.

Figure 15. SOA at 300 kHz Figure 16. SOA at 500 kHz

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0.0 0.2 0.4 0.6 0.8 1.0 1.2

INPUT VOLTAGE (v)

SHORT CIRCUIT VOLTAGE (v)

SAFE OPERATING AREA

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Device Functional Modes (continued)

Figure 17. SOA at 800 kHz

7.4.2 Thermal Protection

Internal thermal shutdown circuitry protects the LM22677 should the maximum junction temperature be

exceeded. This protection is activated at about 150°C, with the result that the regulator will shut down until the

temperature drops below about 135°C.

7.4.3 Duty-Cycle Limits

Ideally the regulator would control the duty cycle over the full range of zero to one. However, due to inherent

delays in the circuitry, there are limits on both the maximum and minimum duty cycles that can be reliably

controlled. This in turn places limits on the maximum and minimum input and output voltages that can be

converted by the LM22677. A minimum on-time is imposed by the regulator in order to correctly measure the

switch current during a current limit event. A minimum off-time is imposed in order the re-charge the bootstrap

capacitor. Equation 8 can be used to determine the approximate maximum input voltage for a given output

voltage.

where

• Fsw is the switching frequency.

• TON is the minimum on-time. (8)

If the frequency adjust feature is used, that value should be used for Fsw. Nominal values should be used. The

worst case is lowest output voltage, and highest switching frequency. If this input voltage is exceeded, the

regulator will skip cycles, effectively lowering the switching frequency. The consequences of this are higher

output voltage ripple and a degradation of the output voltage accuracy.

The second limitation is the maximum duty cycle before the output voltage will "dropout" of regulation. Equation 9

can be used to approximate the minimum input voltage before dropout occurs.

where

• The values of TOFF and RDS(ON) are found in the Electrical Characteristics table. (9)

The worst case here is highest switching frequency and highest load. In Equation 9, RLis the dc inductor

resistance. Of course, the lowest input voltage to the regulator must not be less than 4.5 V (typical).

Product Folder Links: LM22677 LM22677-Q1

Vout

RFBT

RFBB

LM22677

LM22677-Q1

www.ti.com

SNVS582O –SEPTEMBER 2008–REVISED AUGUST 2015

8 Applications 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

The LM22677 is a step-down dc-to-dc regulator. It is typically used to convert a higher dc voltage to a lower dc

voltage with a maximum output current of 5 A. The Detailed Design Procedure can be used to select

components for the LM22677. Alternately, the WEBENCH software may be used to generate complete designs.

When generating a design, the WEBENCH software utilizes iterative design procedures and accesses

comprehensive databases of components. Go to WEBENCH Designer for more details.

8.1.1 Output Voltage Divider Selection

For output voltages between about 1.285 V and 5 V, the -ADJ option should be used, with an appropriate voltage

divider as shown in Figure 18.Equation 10 can be used to calculate the resistor values of this divider:

(10)

A good value for RFBB is 1 kΩ. This will help to provide some of the minimum load current requirement and

reduce susceptibility to noise pick-up. The top of RFBT should be connected directly to the output capacitor or to

the load for remote sensing. If the divider is connected to the load, a local high-frequency bypass should be

provided at that location.

For output voltages of 5 V, the -5.0 option should be used. In this case no divider is needed and the FB pin is

connected to the output. The approximate values of the internal voltage divider are as follows: 7.38 kΩfrom the

FB pin to the input of the error amplifier and 2.55 kΩfrom there to ground.

Both the -ADJ and -5.0 options can be used for output voltages greater than 5 V, by using the correct output

divider. As mentioned in the Internal Compensation section, the -5.0 option is optimized for output voltages of 5

V. However, for output voltages greater than 5 V, this option may provide better loop bandwidth than the

-ADJ option, in some applications. If the -5.0 option is to be used at output voltages greater than 5 V,

Equation 11 should be used to determine the resistor values in the output divider.

(11)

A value of RFBB of about 1 kΩis a good first choice.

Figure 18. Resistive Feedback Divider

A maximum value of 10 kΩis recommended for the sum of RFBB and RFBT to maintain good output voltage

accuracy for the -ADJ option. A maximum of 2 kΩis recommended for the -5.0 option. For the -5.0 option, the

total internal divider resistance is typically 9.93 kΩ.

In all cases the output voltage divider should be placed as close as possible to the FB pin of the LM22677,

because this is a high impedance input and is susceptible to noise pick-up.

Product Folder Links: LM22677 LM22677-Q1

LM22677-ADJ

GND

VIN

BOOT

GND

RT/SYNC

VIN 4.5V to 42V

22 PFC1

6.8 PF

SYNC

10 nF L1

4.7 PH

180 PF

GND

RFBT

1.54 k:

RFBB

976:

60V, 5A

VOUT 3.3V

6.8 PF

LM22677

LM22677-Q1

SNVS582O –SEPTEMBER 2008–REVISED AUGUST 2015

www.ti.com

Application Information (continued)

8.1.2 Power Diode

A Schottky-type power diode is required for all LM22677 applications. Ultra-fast diodes are not recommended

and may result in damage to the IC due to reverse recovery current transients. The near ideal reverse recovery

characteristics and low forward voltage drop of Schottky diodes are particularly important for high input voltage

and low output voltage applications common to the LM22677. The reverse breakdown rating of the diode should

be selected for the maximum VIN, plus some safety margin. A good rule of thumb is to select a diode with a

reverse voltage rating of 1.3 times the maximum input voltage.

Select a diode with an average current rating at least equal to the maximum load current that will be seen in the

application.

8.2 Typical Application

Figure 19 shows an example of converting an input voltage range of 5.5 V to 42 V to an output of 3.3 V at 5 A.

Figure 19. Typical Buck Regulator Application

8.2.1 Design Requirements

DESIGN PARAMETERS EXAMPLE VALUE

Driver Supply Voltage (VIN) 4.5 to 42 V

Output Voltage (VOUT) 3.3 V

RFBT Calculated based on RFBB and VREF of 1.285 V.

RFBB 1 kΩto 10 kΩ

IOUT 5 A

8.2.2 Detailed Design Procedure

8.2.2.1 External Components

The following guidelines should be used when designing a step-down (buck) converter with the LM22677.

8.2.2.2 Inductor

The inductor value is determined based on the load current, ripple current, and the minimum and maximum input

voltages. To keep the application in continuous conduction mode (CCM), the maximum ripple current, IRIPPLE,

should be less than twice the minimum load current.

The general rule of keeping the inductor current peak-to-peak ripple around 30% of the nominal output current is

a good compromise between excessive output voltage ripple and excessive component size and cost. Using this

value of ripple current, the value of inductor, L, is calculated using Equation 12.

where

Product Folder Links: LM22677 LM22677-Q1

LM22677

LM22677-Q1

www.ti.com

SNVS582O –SEPTEMBER 2008–REVISED AUGUST 2015

• Fsw is the switching frequency.

• Vin should be taken at its maximum value, for the given application. (12)

The formula in Equation 12 provides a guide to select the value of the inductor L; the nearest standard value will

then be used in the circuit.

Once the inductor is selected, the actual ripple current can be found from Equation 13.

(13)

Increasing the inductance will generally slow down the transient response but reduce the output voltage ripple.

Reducing the inductance will generally improve the transient response but increase the output voltage ripple.

The inductor must be rated for the peak current, IPK, in a given application, to prevent saturation. During normal

loading conditions, the peak current is equal to the load current plus 1/2 of the inductor ripple current.

During an overload condition, as well as during certain load transients, the controller may trip current limit. In this

case the peak inductor current is given by ICL, found in the Electrical Characteristics table. Good design practice

requires that the inductor rating be adequate for this overload condition.

NOTE

If the inductor is not rated for the maximum expected current, it can saturate resulting in

damage to the LM22677 and/or the power diode.

8.2.2.3 Input Capacitor

The input capacitor selection is based on both input voltage ripple and RMS current. Good quality input

capacitors are necessary to limit the ripple voltage at the VIN pin while supplying most of the regulator current

during switch on-time. Low ESR ceramic capacitors are preferred. Larger values of input capacitance are

desirable to reduce voltage ripple and noise on the input supply. This noise may find its way into other circuitry,

sharing the same input supply, unless adequate bypassing is provided. A very approximate formula for

determining the input voltage ripple is shown in Equation 14.

where

• Vri is the peak-to-peak ripple voltage at the switching frequency. (14)

Another concern is the RMS current passing through this capacitor. Equation 15 gives an approximation to this

current.

(15)

The capacitor must be rated for at least this level of RMS current at the switching frequency.

All ceramic capacitors have large voltage coefficients, in addition to normal tolerances and temperature

coefficients. To help mitigate these effects, multiple capacitors can be used in parallel to bring the minimum

capacitance up to the desired value. This may also help with RMS current constraints by sharing the current

among several capacitors. Many times it is desirable to use an electrolytic capacitor on the input, in parallel with

the ceramics. The moderate ESR of this capacitor can help to damp any ringing on the input supply caused by

long power leads. This method can also help to reduce voltage spikes that may exceed the maximum input

voltage rating of the LM22677.

It is good practice to include a high frequency bypass capacitor as close as possible to the LM22677. This small

case size, low ESR, ceramic capacitor should be connected directly to the VIN and GND pins with the shortest

possible PCB traces. Values in the range of 0.47 µF to 1 µF are appropriate. This capacitor helps to provide a

low impedance supply to sensitive internal circuitry. It also helps to suppress any fast noise spikes on the input

supply that may lead to increased EMI.

Product Folder Links: LM22677 LM22677-Q1

LM22677

LM22677-Q1

SNVS582O –SEPTEMBER 2008–REVISED AUGUST 2015

www.ti.com

8.2.2.4 Output Capacitor

The output capacitor is responsible for filtering the output voltage and supplying load current during transients.

Capacitor selection depends on application conditions as well as ripple and transient requirements. Best

performance is achieved with a parallel combination of ceramic capacitors and a low ESR SP™ or POSCAP™

type. Very low ESR capacitors such as ceramics reduce the output ripple and noise spikes, while higher value

electrolytics or polymers provide large bulk capacitance to supply transients. Assuming very low ESR,

Equation 16 gives an approximation to the output voltage ripple:

(16)

Typically, a total value of 100 µF or greater is recommended for output capacitance.

In applications with Vout less than 3.3 V, it is critical that low ESR output capacitors are selected. This will limit

potential output voltage overshoots as the input voltage falls below the device normal operating range.

If the switching frequency is set higher than 500 kHz, the capacitance value may not be reduced proportionally

due to stability requirements. The internal compensation is optimized for circuits with a 500 kHz switching

frequency. See the Internal Compensation section for more details.

8.2.2.5 Boot-Strap Capacitor

The bootstrap capacitor between the BOOT pin and the SW pin supplies the gate current to turn on the N-

channel MOSFET. The recommended value of this capacitor is 10 nF and should be a good quality, low ESR

ceramic capacitor.

In some cases it may be desirable to slow down the turn-on of the internal power MOSFET, in order to reduce

EMI. This can be done by placing a small resistor in series with the Cboot capacitor. Resistors in the range of 10

Ωto 50 Ωcan be used. This technique should only be used when absolutely necessary, because it will increase

switching losses and thereby reduce efficiency.

8.2.3 Application Curves

Figure 20. Efficiency vs IOUT and VIN, VOUT = 3.3 V Figure 21. Switching Frequency vs RT/SYNC Resistor

Product Folder Links: LM22677 LM22677-Q1

LM22677

LM22677-Q1

www.ti.com

SNVS582O –SEPTEMBER 2008–REVISED AUGUST 2015

9 Power Supply Recommendations

The LM22677 is designed to operate from an input voltage supply range between 4.5 V and 42 V. This input

supply should be able to withstand the maximum input current and maintain a voltage above 4.5 V. The

resistance of the input supply rail should be low enough that an input current transient does not cause a high

enough drop at the LM22677 supply voltage that can cause a false UVLO fault triggering and system reset.

If the input supply is located more than a few inches from the LM22677 additional bulk capacitance may be

required in addition to the ceramic bypass capacitors. The amount of bulk capacitance is not critical, but a 47 µF

or 100 µF electrolytic capacitor is a typical choice.

10 Layout

10.1 Layout Guidelines

Board layout is critical for the proper operation of switching power supplies. First, the ground plane area must be

sufficient for thermal dissipation purposes. Second, appropriate guidelines must be followed to reduce the effects

of switching noise. Switch mode converters are very fast switching devices. In such cases, the rapid increase of

input current combined with the parasitic trace inductance generates unwanted L di/dt noise spikes. The

magnitude of this noise tends to increase as the output current increases. This noise may turn into

electromagnetic interference (EMI) and can also cause problems in device performance. Therefore, care must be

taken in layout to minimize the effect of this switching noise.

The most important layout rule is to keep the ac current loops as small as possible. Figure 22 shows the current

flow in a buck converter. The top schematic shows a dotted line which represents the current flow during the FET

switch on-state. The middle schematic shows the current flow during the FET switch off-state.

The bottom schematic shows the currents referred to as ac currents. These ac currents are the most critical

because they are changing in a very short time period. The dotted lines of the bottom schematic are the traces to

keep as short and wide as possible. This will also yield a small loop area reducing the loop inductance. To avoid

functional problems due to layout, review the PCB layout example. Best results are achieved if the placement of

the LM22677, the bypass capacitor, the Schottky diode, RFBB, RFBT and the inductor are placed as shown in the

example. Note that, in the layout shown, R1 = RFBB and R2 = RFBT. It is also recommended to use 2-oz copper

boards or heavier to help thermal dissipation and to reduce the parasitic inductances of board traces. See

application note AN-1229 SIMPLE SWITCHER ® PCB Layout Guidelines (SNVA054) for more information.

Figure 22. Current Flow in a Buck Application

Product Folder Links: LM22677 LM22677-Q1

LM22677

LM22677-Q1

SNVS582O –SEPTEMBER 2008–REVISED AUGUST 2015

www.ti.com

10.2 Layout Example

Figure 23. PCB Layout Example

Product Folder Links: LM22677 LM22677-Q1

LM22677

LM22677-Q1

www.ti.com

SNVS582O –SEPTEMBER 2008–REVISED AUGUST 2015

10.3 Thermal Considerations

The components with the highest power dissipation are the power diode and the power MOSFET internal to the

LM22677 regulator. The easiest method to determine the power dissipation within the LM22677 is to measure

the total conversion losses then subtract the power losses in the diode and inductor. The total conversion loss is

the difference between the input power and the output power. An approximation for the power diode loss is in

Equation 17.

where

• VDis the diode voltage drop. (17)

An approximation for the inductor power is shown in Equation 18.

where

• RLis the dc resistance of the inductor.

• The 1.1 factor is an approximation for the ac losses. (18)

The regulator has an exposed thermal pad to aid power dissipation. Adding multiple vias under the device to the

ground plane will greatly reduce the regulator junction temperature. Selecting a diode with an exposed pad will

also aid the power dissipation of the diode. The most significant variables that affect the power dissipation of the

regulator are output current, input voltage and operating frequency. The power dissipated while operating near

the maximum output current and maximum input voltage can be appreciable. The junction-to-ambient thermal

resistance of the LM22677 will vary with the application. The most significant variables are the area of copper in

the PC board, the number of vias under the IC exposed pad and the amount of forced air cooling provided. A

large continuos ground plane on the top of bottom PCB layer will provide the most effective heat dissipation. The

integrity of the solder connection from the IC exposed pad to the PC board is critical. Excessive voids will greatly

diminish the thermal dissipation capacity. The junction-to-ambient thermal resistance of the LM22677 NDR

package is specified in the Electrical Characteristics table. See AN-2020 Thermal Design By Insight, Not

Hindsight (SNVA419) for more information.

Product Folder Links: LM22677 LM22677-Q1

LM22677

LM22677-Q1

SNVS582O –SEPTEMBER 2008–REVISED AUGUST 2015

www.ti.com

11 Device and Documentation Support

11.1 Documentation Support

11.1.1 Related Documentation

•AN-1889 How to Measure the Loop Transfer Function of Power Supplies (SNVA364)

•AN-1892 LM22677 Evaluation Board (SNVA366)

•AN-1229 SIMPLE SWITCHER ® PCB Layout Guidelines (SNVA054)

•AN-2020 Thermal Design By Insight, Not Hindsight (SNVA419)

11.2 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 1. Related Links

TECHNICAL TOOLS & SUPPORT &

PARTS PRODUCT FOLDER SAMPLE & BUY DOCUMENTS SOFTWARE COMMUNITY

LM22677 Click here Click here Click here Click here Click here

LM22677-Q1 Click here Click here Click here Click here Click here

11.3 Trademarks

SIMPLE SWITCHER, WEBENCH are registered trademarks of Texas Instruments.

All other trademarks are the property of their respective owners.

11.4 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.

11.5 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: LM22677 LM22677-Q1

PACKAGE OPTION ADDENDUM

www.ti.com 10-Dec-2020

Addendum-Page 1

PACKAGING INFORMATION

Orderable Device Status

(1)

Package Type Package

Drawing Pins Package

Qty Eco Plan

(2)

Lead finish/

Ball material

(6)

MSL Peak Temp

(3)

Op Temp (°C) Device Marking

(4/5)

Samples

LM22677QTJ-ADJ/NOPB ACTIVE TO-263 NDR 7 1000 RoHS & Green SN Level-1-260C-UNLIM -40 to 125 LM22677

QTJ-ADJ

LM22677QTJE-5.0/NOPB ACTIVE TO-263 NDR 7 250 RoHS & Green SN Level-1-260C-UNLIM -40 to 125 LM22677

QTJ-5.0

LM22677QTJE-ADJ/NOPB ACTIVE TO-263 NDR 7 250 RoHS & Green SN Level-1-260C-UNLIM -40 to 125 LM22677

QTJ-ADJ

LM22677TJ-5.0/NOPB ACTIVE TO-263 NDR 7 1000 RoHS & Green SN Level-1-260C-UNLIM -40 to 125 LM22677

TJ-5.0

LM22677TJ-ADJ/NOPB ACTIVE TO-263 NDR 7 1000 RoHS & Green SN Level-1-260C-UNLIM -40 to 125 LM22677

TJ-ADJ

LM22677TJE-5.0/NOPB ACTIVE TO-263 NDR 7 250 RoHS & Green SN Level-1-260C-UNLIM -40 to 125 LM22677

TJ-5.0

LM22677TJE-ADJ/NOPB ACTIVE TO-263 NDR 7 250 RoHS & Green SN Level-1-260C-UNLIM -40 to 125 LM22677

TJ-ADJ

(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.

PACKAGE OPTION ADDENDUM

www.ti.com 10-Dec-2020

Addendum-Page 2

(6) Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material 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

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 LM22677, LM22677-Q1 :

•Catalog: LM22677

•Automotive: LM22677-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

LM22677QTJ-ADJ/NOPB TO-263 NDR 7 1000 330.0 24.4 10.6 15.4 2.45 12.0 24.0 Q2

LM22677QTJE-5.0/NOPB TO-263 NDR 7 250 178.0 24.4 10.6 15.4 2.45 12.0 24.0 Q2

LM22677QTJE-ADJ/NOP

BTO-263 NDR 7 250 178.0 24.4 10.6 15.4 2.45 12.0 24.0 Q2

LM22677TJ-5.0/NOPB TO-263 NDR 7 1000 330.0 24.4 10.6 15.4 2.45 12.0 24.0 Q2

LM22677TJ-ADJ/NOPB TO-263 NDR 7 1000 330.0 24.4 10.6 15.4 2.45 12.0 24.0 Q2

LM22677TJE-5.0/NOPB TO-263 NDR 7 250 178.0 24.4 10.6 15.4 2.45 12.0 24.0 Q2

LM22677TJE-ADJ/NOPB TO-263 NDR 7 250 178.0 24.4 10.6 15.4 2.45 12.0 24.0 Q2

PACKAGE MATERIALS INFORMATION

www.ti.com 2-Sep-2015

Pack Materials-Page 1

*All dimensions are nominal

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

LM22677QTJ-ADJ/NOPB TO-263 NDR 7 1000 367.0 367.0 35.0

LM22677QTJE-5.0/NOPB TO-263 NDR 7 250 210.0 185.0 35.0

LM22677QTJE-ADJ/NOPB TO-263 NDR 7 250 210.0 185.0 35.0

LM22677TJ-5.0/NOPB TO-263 NDR 7 1000 367.0 367.0 35.0

LM22677TJ-ADJ/NOPB TO-263 NDR 7 1000 367.0 367.0 35.0

LM22677TJE-5.0/NOPB TO-263 NDR 7 250 210.0 185.0 35.0

LM22677TJE-ADJ/NOPB TO-263 NDR 7 250 210.0 185.0 35.0

PACKAGE MATERIALS INFORMATION

www.ti.com 2-Sep-2015

Pack Materials-Page 2

www.ti.com

PACKAGE OUTLINE

-60

10.1

9.6

10.41

9.91

2.1

1.9

1.05

0.95

10.76

10.26

12.45

11.95

14.36

13.66

0-0.15

STAND-OFF

NOTE 5

R0.7

MAX TYP

ALL AROUND

(2.66) 6.5

6.1

5.75

5.40

7.1

6.5

6.6

6.3

4.1

3.9

1.05

0.65

6.11

5.85

7X 0.735

0.635

6X 1.27

7.62

7X 0.508

0.381

4219872/A 04/2019

TO-263 - 2.25 mm max heightNDR0007A

TO-263

NOTES:

1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing

per ASME Y14.5M.

2. This drawing is subject to change without notice.

3. Features may not exist and shape may vary per different assembly sites.

4. Reference JEDEC registration TO-279B.

5. Under all conditions, leads must not be above Datum C

SCALE 1.000

0.15

0.25 C A B 1

PIN 1 ID

EXPOSED PAD

(OUTLINE DOES NOT

INCLUDE MOLD FLASH)

www.ti.com

EXAMPLE BOARD LAYOUT

0.07 MAX

ALL AROUND 0.07 MIN

ALL AROUND

(6.35)

(5.59)

(0.91)(8.28)

6X (1.27)

(7.62)

7X (2.41)

7X (0.91)

4219872/A 04/2019

TO-263 - 2.25 mm max heightNDR0007A

TO-263

NOTES: (continued)

6. This package is designed to be soldered to a thermal pad on the board. For more information, see Texas Instruments literature numbers

SLMA002(www.ti.com/lit/slm002) and SLMA004 (www.ti.com/lit/slma004).

7. Vias are optional depending on application, refer to device data sheet. It is recommended that vias under paste be filled, plugged or tented.

OPENING

SOLDER MASK METAL

NON SOLDER MASK

DEFINED

SOLDER MASK DETAILS

EXPOSED

METAL

SOLDER MASK

OPENING

SOLDER MASK

METAL UNDER

SOLDER MASK

DEFINED

EXPOSED

METAL

SYMM

PKG

www.ti.com

EXAMPLE STENCIL DESIGN

20X (1)

20X (1.13)

R(0.05) TYP

(1.2) TYP

(1.33) TYP

(0.665)

(0.29)

0.91(8.28)

(7.62)

6X (1.27)

7X (2.41) 7X (0.91)

4219872/A 04/2019

TO-263 - 2.25 mm max heightNDR0007A

TO-263

NOTES: (continued)

8. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate

design recommendations.

9. Board assembly site may have different recommendations for stencil design.

SOLDER PASTE EXAMPLE

BASED ON 0.125 mm THICK STENCIL

EXPOSED PAD

64% PRINTED SOLDER COVERAGE BY AREA

SCALE:7X

8SYMM

PKG

EXPOSED METAL

TYP

IMPORTANT NOTICE AND DISCLAIMER

TI PROVIDES TECHNICAL AND RELIABILITY DATA (INCLUDING DATASHEETS), DESIGN RESOURCES (INCLUDING REFERENCE

DESIGNS), APPLICATION OR OTHER DESIGN ADVICE, WEB TOOLS, SAFETY INFORMATION, AND OTHER RESOURCES “AS IS”

AND WITH ALL FAULTS, AND DISCLAIMS ALL WARRANTIES, EXPRESS AND IMPLIED, INCLUDING WITHOUT LIMITATION ANY

IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT OF THIRD

PARTY INTELLECTUAL PROPERTY RIGHTS.

These resources are intended for skilled developers designing with TI products. You are solely responsible for (1) selecting the appropriate

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