MAX16816ATJ+ - Maxim Integrated

General Description

The MAX16816 is a current-mode, high-brightness LED

(HB LED) driver designed to control two external n-channel

MOSFETs for single-string LED current regulation. The

MAX16816 integrates all the building blocks necessary to

implement fixed-frequency HB LED drivers with wide-range

dimming control and EEPROM-programmable LED current

binning with a factor of up to 1.6. This device is configurable

to operate as a step-down (buck), step-up (boost), or step-up/

step-down (buck-boost) current regulator.

Current-mode control with adjustable leading-edge

blanking simplifies control-loop design. Adjustable slope

compensation stabilizes the current loop when operating

at duty cycles above 50%. The MAX16816 operates over

a wide input voltage range and is capable of withstand-

ing load-dump events. Multiple MAX16816 devices can

be synchronized to each other or to an external clock.

The MAX16816 includes a floating dimming driver for

brightness control with an external n-channel MOSFET in

series with the LED string.

HB LEDs using the MAX16816 can achieve efficiencies of

over 90%. The MAX16816 also includes a 1.4A source and

2A sink gate driver for driving switching MOSFETs in high-

power LED driver applications, such as front light assem-

blies. Dimming control allows for wide PWM dimming

range at frequencies up to 5kHz. Higher dimming ratios (up

to 1000:1) are achievable at lower dimming frequencies.

The MAX16816 provides user-programmable

features through on-chip nonvolatile EEPROM registers.

Adjustable features include a programmable soft-start,

LED current (binning), external MOSFET gate driver

supply voltage, slope compensation, leading-edge blank-

ing time, and disabling/enabling of the RT oscillator.

The MAX16816 is available in a 32-pin TQFN package

with exposed pad and operates over the -40°C to +125°C

automotive temperature range.

Applications

●General Illumination

●Navigation and Marine Indicators

●Neon Replacement, Emergency Lighting

●Signage and Beacons

Features

●EEPROM-Programmable LED Current Binning

●Wide Input Range: 5.9V to 76V with Cold-Start

Operation to 5.4V

●Integrated Floating Differential LED Current-Sense

Amplifier

●Floating Dimming Driver Capable of Driving an

n-Channel MOSFET

●5% or Better LED Current Accuracy

●Multiple Topologies: Buck, Boost, Buck-Boost, SEPIC

●Resistor-Programmable Switching Frequency (125kHz

to 500kHz) and Synchronization Capability

●200Hz On-Board Ramp Allows Analog-Controlled

PWM Dimming and External PWM Dimming

●Output Overvoltage, Overcurrent, and LED Short

Protection

●Enable/Shutdown Input with Shutdown Current Below 45μA

Pin Configuration appears at end of data sheet. Typical Operating Circuits continued at end of data sheet.

19-1054; Rev 1; 4/15

+Denotes a lead(Pb)-free/RoHS-compliant package.

**EP = Exposed pad.

PART TEMP RANGE PIN-

PACKAGE

PKG

CODE

MAX16816ATJ+ -40°C to +125°C 32 TQFN-EP* T3255M-4

VIN

DIM

RCS

CREG1

RUV2

DRV

DRI

REG1

DIM

FAULT

VCC

SNS+

QGND

RTSYNC

CS- CS+

COMP REG2

DGT

UVEN

SNS-

AGND

RSENSE

ROV1

ROV2

CLMP

SGND

CCLMP

CREG2

LEDs

BUCK-BOOST CONFIGURATION

RUV1

CUVEN

MAX16816

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

Typical Operating Circuits

Ordering Information

EVALUATION KIT AVAILABLE

VCC, HI, LO, CLMP to QGND ...............................-0.3V to +80V

CS+, CS-, DGT, UVEN, FAULT to QGND ............. -0.3V to +80V

UVEN to QGND ........................................ -0.3V to (VCC + 0.3V)

DRV to SGND .......................................................-0.3V to +18V

DRI, REG2, DIM to AGND ....................................-0.3V to +18V

QGND, SGND to AGND ...................................... .-0.3V to +0.3V

SNS+ to SNS- .........................................................-0.3V to +6V

CS, FB, COMP, SNS+, SNS-, OV, REF,

RTSYNC to AGND ...............................................-0.3V to +6V

REG1, CLKOUT to AGND ....................................... -0.3V to +6V

CS+ to CS- ............................................................-0.3V to +12V

HI to LO .................................................................-0.3V to +36V

CS+, CS-, DGT, CLMP to LO ................................ -0.3V to +12V

CS+, CS-, DGT, CLMP to LO .......................-0.3V to (HI + 0.3V)

HI to CLMP ............................................................-0.3V to +28V

Continuous Power Dissipation* (TA = +70°C)

32-Pin TQFN (derate 34.5mW/°C above +70°C) ......2758mW

Operating Temperature Range ......................... -40°C to +125°C

Maximum Junction Temperature .....................................+150°C

Storage Temperature Range ............................ -60°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

*As per JEDEC 51 standard, Multilayer Board (PCB).

(VCC = VUVEN = 14V, CREG1 = 1μF, CREG2 = 1μF, CCLMP = 0.1μF, RT = 25kΩ, TA = TJ = -40°C to +125°C, unless otherwise noted.

Typical specifications are at TA = +25°C.)

Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer

board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Input Voltage Range VCC 5.5 76 V

Supply Current to VCC IQ_VCC Exclude current to the gate driver, IREG2 2.7 4.5 mA

Supply Current to HI IQ_HI VHI = 14V 0.5 1.0 mA

Shutdown Current to VCC ISHDN_VCC VUVEN ≤ 300mV 25 45 µA

Shutdown Current to HI ISHDN_HI VUVEN ≤ 300mV 1 10 µA

UVEN

VCC UVLO Threshold VCC_R VCC rising 5.5 6.0 V

VCC_F VCC falling 5.0 5.5

VCC Threshold Hysteresis VCC_HYS 0.4 V

UVEN Threshold VUVR VUVEN rising 1.10 1.244 1.36 V

VUVF VUVEN falling 1.00 1.145 1.26

UVEN Input Current IUVEN

(VUVEN = 0V and VCC = 14V) (VUVEN = 76V

and VCC = 77V) -0.2 +0.2 µA

REGULATORS

REG1 Regulator Output VREG1

0 < IREG1 < 2mA, 7.5V < VCC < 76V 4.75 5.00 5.25 V

IREG1 = 2mA, VCC = 5.7V 4.00 4.50 5.25

REG1 Dropout Voltage IREG1 = 2mA (Note 1) 0.5 1.0 V

REG1 Load Regulation ΔV/ΔI VCC = 7.5V, IREG1 = 0 to 2mA 25 Ω

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

www.maximintegrated.com Maxim Integrated

│

Absolute Maximum Ratings

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these

or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect

device reliability.

Electrical Characteristics

Junction-to-Ambient Thermal Resistance (θJA) ............29°C/W

Junction-to-Case Thermal Resistance (θJC) ................1.7°C/W

Package Thermal Characteristics (Note 1)

(VCC = VUVEN = 14V, CREG1 = 1μF, CREG2 = 1μF, CCLMP = 0.1μF, RT = 25kΩ, TA = TJ = -40°C to +125°C, unless otherwise noted.

Typical specifications are at TA = +25°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

REG2 Dropout Voltage VCC ≥ 9.5V, REG2 control register is ‘0011’,

IREG2 = 20mA (Note 1) 0.5 1.0 V

REG2 Load Regulation ΔV/ΔI VCC ≥ 9.5V, REG2 control register is ‘0011’,

IREG2 = 0 to 20mA 25 Ω

REG2 Regulation Voltage

REG2 control register is ‘0000’,

VCC ≥ 7.5V, IREG2 = 1mA 4.75 5 5.25

REG2 control register is ‘0011’,

VCC ≥ 9.5V, IREG2 = 1mA 6.65 7.0 7.35

REG2 control register is ‘1111’,

VCC ≥ 17.5V, IREG2 = 1mA 13.5 15 16.5

REG2 control register is ‘0000’,

VCC = 5.7V, 0 ≤ IREG2 ≤ 20mA 4 4.5 5.25

REG2 control register is ‘0000’,

VCC = 7.5V, 0 ≤ IREG2 ≤ 20mA 4.75 5 5.25

REG2 control register is ‘1111’,

VCC = 17.5V, 0 ≤ IREG2 ≤ 20mA 13.5 15 16.5

HIGH-SIDE REGULATOR (CLMP) (All voltages referred to VLO) (Note 3)

CLMP UVLO Threshold VCLMP_TH VCLMP rising 2.0 2.5 3.0 V

CLMP UVLO Threshold

Hysteresis VCLMP_HYS 0.22 V

CLMP Regulator Output

Voltage VCLMP

8.7V ≤ (VHI - VLO) ≤ 36V, ICLMP = 1mA 5.5 8.0 10.0 V

5.0V ≤ (VHI - VLO) ≤ 8.7V, ICLMP = 250µA (VHI - VLO) - 0.7

CURRENT-SENSE AMPLIFIER (CSA)

Differential Input Voltage

Range VCS+ - VCS- 0 0.3 V

Common-Mode Range VCC ≤ 68V 0 VCC V

CS+ Input Bias Current ICS+ VCS+ = 0.3V, VCS- = 0V -250 +250 nA

CS- Input Bias Current ICS- VCS+ = 0.3V, VCS- = 0V 400 µA

Unity-Gain Bandwidth From (CS+ to CS-) to CS 1.0 MHz

REF OUTPUT BUFFER

REF Output Voltage VREF -100µA ≤ IL ≤ +100µA 2.85 3.0 3.15 V

DIM DRIVER

Minimal Pulse Width fDIM = 200Hz (Note 4) 20 40 µs

Source Current VCLMP - VLO = 4V 5 20 mA

VCLMP - VLO = 8V 30 67

Sink Current VCLMP - VLO = 4V 10 22 mA

VCLMP - VLO = 8V 40 76

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

www.maximintegrated.com Maxim Integrated

│

Electrical Characteristics (continued)

(VCC = VUVEN = 14V, CREG1 = 1μF, CREG2 = 1μF, CCLMP = 0.1μF, RT = 25kΩ, TA = TJ = -40°C to +125°C, unless otherwise noted.

Typical specifications are at TA = +25°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

GATE DRIVER

DRI Voltage Range VDRI VCC ≥ 2.5V above VDRI 5 15 V

DRI UVLO Threshold VUVLO_TH 4.0 4.2 4.4 V

DRI UVLO Threshold Hysteresis VUVLO_HYST 0.3 V

Driver Output Impedance ZOUT_L VDRI = 7.0V, DRV sinking 250mA 2.8 4 Ω

ZOUT_H VDRI = 7.0V, DRV sourcing 250mA 5.0 8

Peak Sink Current ISK VDRI = 7.0V 2.5 A

Peak Source Current ISR VDRI = 7.0V 1.4 A

PWM, ILIM, AND HICCUP COMPARATOR

PWM Comparator Offset Voltage VCOMP - (VSNS+ -VSNS-) 0.8 V

Peak Current-Limit Comparator

Trip Threshold 160 200 245 mV

Peak Current-Limit Comparator

Propagation Delay (Excluding

Blanking Time)

50mV overdrive 40 ns

HICCUP Comparator Trip

Threshold 235 300 385 mV

SNS+ Input Bias Current VSNS+ = 0V, VSNS- = 0V -100 -65 µA

SNS- Input Bias Current VSNS+ = 0V, VSNS- = 0V -100 -65 µA

BLANKING TIME

Blanking Time

Blanking Time Control Register is ‘00’ 150

Blanking Time Control Register is ‘01’ 125

Blanking Time Control Register is ‘10’ 100

Blanking Time Control Register is ‘11’ 75

ERROR AMPLIFIER

FB Input Bias Current VFB = 1V -100 +100 nA

EAMP Output Sink Current VFB = 1.735V, VCOMP = 1V 3 7 mA

EAMP Output Source Current VFB = 0.735V, VCOMP = 1V 2 7 mA

EAMP Input Common-Mode

Voltage VCOM (Note 5) 0 1.6 V

EAMP Output Clamp Voltage 1.3 2.0 2.7 V

Voltage Gain AVRCOMP = 100kΩ to AGND 80 dB

Unity-Gain Bandwidth GBW RCOMP = 100kΩ to AGND,

CCOMP = 100pF to AGND 0.5 MHz

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

www.maximintegrated.com Maxim Integrated

│

Electrical Characteristics (continued)

(VCC = VUVEN = 14V, CREG1 = 1μF, CREG2 = 1μF, CCLMP = 0.1μF, RT = 25kΩ, TA = TJ = -40°C to +125°C, unless otherwise noted.

Typical specifications are at TA = +25°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

OSCILLATOR, OSC SYNC, CLK, AND CLKOUT

SYNC Frequency Range fSW_MIN 125 kHz

fSW_MAX 500

RTSYNC Oscillator Frequency RTOF bit set to ‘0’, RT = 100kΩ 106 125 143 kHz

RTOF bit set to ‘0’, RT = 25kΩ 475 500 525

SYNC High-Level Voltage VSIHL 2.8 V

SYNC Low-Level Voltage VSILL 0.4 V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

CLKOUT High Level ISINK = 0.8mA 2.8 V

CLKOUT Low Level ISOURCE = 1.6mA 0.4 V

CLKOUT Maximum Load

Capacitance CCLK_CAP fSW = 500kHz 500 pF

DIM SYNC, DIM RAMP, AND DIM PWM GEN

Internal RAMP Frequency fRAMP 160 200 240 Hz

External Sync Frequency

Range fDIM 80 2000 Hz

External Sync Low-Level

Voltage VLTH 0.4 V

External Sync High-Level

Voltage VHTH 3.2 V

DIM Comparator Offset VDIMOS 170 200 300 mV

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

www.maximintegrated.com Maxim Integrated

│

Electrical Characteristics (continued)

(VCC = VUVEN = 14V, CREG1 = 1μF, CREG2 = 1μF, CCLMP = 0.1μF, RT = 25kΩ, TA = TJ = -40°C to +125°C, unless otherwise noted.

Typical specifications are at TA = +25°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

DIGITAL SOFT-START AND BINNING

Soft-Start Duration tSS

Digital Soft-Start Duration register is ‘000’ 4096

µs

Digital Soft-Start Duration register is ‘001’ 2048

Digital Soft-Start Duration register is ‘010’ 1536

Digital Soft-Start Duration register is ‘011’ 1024

Digital Soft-Start Duration register is ‘100’ 768

Digital Soft-Start Duration register is ‘101’ 512

Digital Soft-Start Duration register is ‘110’ 256

Digital Soft-Start Duration register is ‘111’ 0

Binning Range

Binning Adjustment register is ‘0000’ 100.00

Binning Adjustment register is ‘0001’ 106.67

Binning Adjustment register is ‘0010’ 113.33

Binning Adjustment register is ‘0011’ 120.00

Binning Adjustment register is ‘0100’ 126.67

Binning Adjustment register is ‘0101’ 133.33

Binning Adjustment register is ‘0110’ 140.00

Binning Adjustment register is ‘0111’ 146.67

Binning Adjustment register is ‘1000’ 153.33

Binning Adjustment register is ‘1001’ 160.00

Binning Adjustment register is ‘1010’ 166.67

OVERVOLTAGE COMPARATOR, LOAD OVERCURRENT COMPARATOR

OVP Overvoltage

Comparator Threshold VOV VOV rising 1.20 1.235 1.27 V

OVP Overvoltage

Comparator Hysteresis VOV_HYST 63.5 mV

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

www.maximintegrated.com Maxim Integrated

│

Electrical Characteristics (continued)

(VCC = VUVEN = 14V, CREG1 = 1μF, CREG2 = 1μF, CCLMP = 0.1μF, RT = 25kΩ, TA = TJ = -40°C to +125°C, unless otherwise noted.

Typical specifications are at TA = +25°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

SLOPE COMPENSATION

Slope Compensation Peak-

to-Peak Voltage Per Cycle

Slope Compensation register is ‘0000’,

clock generated by RT

mV/

cycle

Slope Compensation register is ‘0001’,

clock generated by RT

Slope Compensation register is ‘0010’,

clock generated by RT

Slope Compensation register is ‘0011’,

clock generated by RT

Slope Compensation register is ‘0100’,

clock generated by RT

Slope Compensation register is ‘0101’,

clock generated by RT

100

Slope Compensation register is ‘0110’,

clock generated by RT

120

Slope Compensation register is ‘0111’,

clock generated by RT

140

Slope Compensation register is ‘1000’,

clock generated by RT

160

Slope Compensation register is ‘1001’,

clock generated by RT

180

Slope Compensation register is ‘1010’,

clock generated by RT

200

Slope Compensation register is ‘1011’,

clock generated by RT

220

Slope Compensation register is ‘1100’,

clock generated by RT

240

Slope Compensation register is ‘1101’,

clock generated by RT

260

Slope Compensation register is ‘1110’,

clock generated by RT

280

Slope Compensation register is ‘1111’,

clock generated by RT

300

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

www.maximintegrated.com Maxim Integrated

│

Electrical Characteristics (continued)

(VCC = VUVEN = 14V, CREG1 = 1μF, CREG2 = 1μF, CCLMP = 0.1μF, RT = 25kΩ, TA = TJ = -40°C to +125°C, unless otherwise noted.

Typical specifications are at TA = +25°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Slope Compensation

Slope Compensation register is ‘0000’,

external clock applied to RTSYNC 0

mV/µs

Slope Compensation register is ‘0001’,

external clock applied to RTSYNC 2

Slope Compensation register is ‘0010’,

external clock applied to RTSYNC 4

Slope Compensation register is ‘0011’,

external clock applied to RTSYNC 6

Slope Compensation register is ‘0100’,

external clock applied to RTSYNC 8

Slope Compensation register is ‘0101’,

external clock applied to RTSYNC 10

Slope Compensation register is ‘0110’,

external clock applied to RTSYNC 12

Slope Compensation register is ‘0111’,

external clock applied to RTSYNC 14

Slope Compensation register is ‘1000’,

external clock applied to RTSYNC 16

Slope Compensation register is ‘1001’,

external clock applied to RTSYNC 18

Slope Compensation register is ‘1010’,

external clock applied to RTSYNC 20

Slope Compensation register is ‘1011’,

external clock applied to RTSYNC 22

Slope Compensation register is ‘1100’,

external clock applied to RTSYNC 24

Slope Compensation register is ‘1101’,

external clock applied to RTSYNC 26

Slope Compensation register is ‘1110’,

external clock applied to RTSYNC 28

Slope Compensation register is ‘1111’,

external clock applied to RTSYNC 30

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

www.maximintegrated.com Maxim Integrated

│

Electrical Characteristics (continued)

(CREG1 = 1μF, CREG2 = 1μF, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical specifications are at TA = +25°C.)

1-Wire is a registered trademark of Maxim Integrated Products, Inc.

Electrical Characteristics – 1-Wire® System

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

I/O GENERAL DATA

1-Wire Time Slot Duration tSLOT 65 µs

Recovery Time tREC (Note 7) 5 µs

I/O, 1-Wire RESET, PRESENCE DETECT CYCLE

Reset Low Time tRSTL 480 640 µs

Presence Detect Sample Time tMSP 65 75 µs

I/O, 1-Wire WRITE

Write-0 Low Time tW0L 60 µs

Write-1 Low Time tW1L 5 15 µs

I/O, 1-Wire READ

Read Low Time tRL 5 10 µs

Read Sample Time tMSR 12 15 µs

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

FAULT I/O

FAULT Leakage Current 5.5V < VFAULT < 76V -1 +1 µA

FAULT Input Low Current VFAULT = 0V 500 µA

FAULT Pulldown Current VFAULT = 2V 0.7 1.2 1.8 mA

FAULT Pulldown Input

Logic-Low VIL 0.4 V

FAULT Output Logic-High Sourcing 10µA 2.8 V

FAULT Output Logic-Low Sinking 10µA 0.4 V

Programming Slot at Power-

Up VUVEN > 1.244V and VCC > 5.9V (Note 4) 6.4 8.0 ms

THERMAL SHUTDOWN

Thermal Shutdown

Temperature TJ_SHDN +165 °C

Thermal Shutdown

Hysteresis ΔTJ_SHDN 20 °C

EEPROM

Data Retention tDR TA = +125°C (Note 5) 10 years

EEPROM Write Time tWRA (Note 5) 14 ms

Endurance TA = +85°C, read and write (Note 5) 50k cycles

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

www.maximintegrated.com Maxim Integrated

│

(VCC = VUVEN = 14V, CREG1 = 1μF, CREG2 = 1μF, CCLMP = 0.1μF, RT = 25kΩ, TA = TJ = -40°C to +125°C, unless otherwise noted.

Typical specifications are at TA = +25°C.)

Electrical Characteristics (continued)

Note 2: Dropout voltage is defined as the input to output differential voltage at which the output voltage drops 100mV below its nominal

value measured at output.

Note 3: VCLMP_TH determines the voltage necessary to operate the current-sense amplifier. The DIM driver requires 2.5V for (VCLMP

- VLO) to drive a FET. VHI is typically one diode drop above VCLMP. A large capacitor connected to VCLMP slows the response

of the LED current-sense circuitry, resulting in current overshoot. To ensure proper operation, connect a 0.1μF capacitor from

CLMP to LO.

Note 4: Minimum pulse width required to guarantee proper dimming operation.

Note 5: FAULT multiplexes a programming interface and fault-indication functionality. At power-up initialization, an internal timer

enables FAULT and two programming passcodes must be entered within the programming slot to enter programming mode.

If the programming passcodes are not received correctly within the programming slot, FAULT goes back towards fault indica-

tion. Cycling power to the device is required to re-attempt entry into programming mode.

Note 6: Not production tested. Guaranteed by design.

Note 7: Recovery time is the time required for FAULT to be pulled high by the internal 10kΩ resistor.

(VCC = VUVEN = 14V, CREG1 = 1μF, CREG2 = 10μF, CCLMP = 0.1μF, RCS = 0.1Ω, Binning adjustment register is ‘0000’, TA = +25°C,

unless otherwise noted.)

OPERATING CURRENT

vs. TEMPERATURE

MAX16816 toc02

TEMPERATURE (°C)

ICC (mA)

120100806040200-20-40

2.8

3.0

3.2

3.4

3.6

3.8

4.0

2.6

-60 140

DGT AND DRV

NOT SWITCHING

OUTPUT CURRENT

vs. TEMPERATURE

MAX16816 toc03

TEMPERATURE (°C)

LED CURRENT (mA)

120100-40 -20 0 40 6020 80

250

300

350

400

450

500

550

600

200

-60 140

RCS = 0.2Ω

RCS = 0.3Ω

SHUTDOWN CURRENT

vs. TEMPERATURE

MAX16816 toc01

TEMPERATURE (°C)

ISHDN_VCC (µA)

120100-40 -20 0 40 6020 80

-60 140

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

www.maximintegrated.com Maxim Integrated

│

Electrical Characteristics (continued)

Typical Operating Characteristics

(VCC = VUVEN = 14V, CREG1 = 1μF, CREG2 = 10μF, CCLMP = 0.1μF, RCS = 0.1Ω, Binning adjustment register is ‘0000’, TA = +25°C,

unless otherwise noted.)

OUTPUT CURRENT

vs. BINNING CODES

MAX16816 toc05

BIN (DIGITAL CODE)

LED CURRENT (A)

875 62 3 41

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0 9

OUTPUT CURRENT

vs. BINNING CODES

MAX16816 toc06

BIN (DIGITAL CODE)

OUTPUT CURRENT (mA)

875 62 3 41

100

200

300

400

500

600

700

800

900

0 9

RCS = 0.2Ω

REG2 OUTPUT VOLTAGE

vs. TEMPERATURE

MAX16816 toc07

TEMPERATURE (°C)

REG2 OUTPUT VOLTAGE (V)

12010060 80-20 0 20 40-40

-60 140

IREG2 = 20mA

REG2 CONTROL REGISTER = '1111',

VCC = 20V

REG2 CONTROL REGISTER = '0000'

REG2 OUTPUT VOLTAGE

vs. SUPPLY VOLTAGE

MAX16816 toc08

VCC (V)

REG2 OUTPUT VOLTAGE (V)

726448 5616 24 32 408

0 80

IREG2 = 20mA

REG2 CONTROL REGISTER =

'1111', VCC = 20V

REG2 CONTROL REGISTER = '0000'

REG2 OUTPUT VOLTAGE

vs. REG2 CONTROL REGISTER

MAX16816 toc09

DRPS (DIGITAL CODE)

REG2 OUTPUT VOLTAGE (V)

10 113 4 5 6 7 8 91 2

014 15

IREG2 = 20mA

REG1 OUTPUT VOLTAGE

vs. TEMPERATURE

MAX16816 toc10

TEMPERATURE (°C)

REG1 OUTPUT VOLTAGE (V)

120100-40 -20 0 40 6020 80

4.7

4.8

4.9

5.0

5.1

5.2

5.3

5.4

4.6

-60 140

IREG1 = 2mA

OUTPUT CURRENT

vs. SUPPLY VOLTAGE

MAX16816 toc04

VCC (V)

LED CURRENT (mA)

72645648403224168

100

150

200

250

300

350

0 80

REG1 OUTPUT VOLTAGE

vs. SUPPLY VOLTAGE

MAX16816 toc11

VCC (V)

REG1 OUTPUT VOLTAGE (V)

70605040302010

0 80

IREG1 = 2mA

CLMP OUTPUT VOLTAGE

vs. TEMPERATURE

MAX16816 toc12

TEMPERATURE (°C)

CLMP OUTPUT VOLTAGE (V)

120100-40 -20 0 40 6020 80

7.6

7.7

7.8

7.9

8.0

8.1

8.2

8.3

7.5

-60 140

VHI - VLO = 9V

CLMP VOLTAGE = VCLMP - VLO

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

Maxim Integrated

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www.maximintegrated.com

Typical Operating Characteristics (continued)

(VCC = VUVEN = 14V, CREG1 = 1μF, CREG2 = 10μF, CCLMP = 0.1μF, RCS = 0.1Ω, Binning adjustment register is ‘0000’, TA = +25°C,

unless otherwise noted.)

REF VOLTAGE

vs. SINK CURRENT

MAX16816 toc14

IREF (µA)

REF VOLTAGE (V)

1751257525-25-75-125-175

3.005

3.010

3.015

3.020

3.025

3.000

-225 225

PWM OSCILLATION FREQUENCY

vs. TEMPERATURE

MAX16816 toc15

TEMPERATURE (°C)

PWM FREQUENCY (kHz)

11590-35 -10 15 40 65

122

126

132

131

130

129

128

127

124

123

121

125

133

134

135

120

-60 140

RT = 100kΩ

RT RESISTANCE

vs. PWM FREQUENCY

MAX16816 toc16

1/RT RESISTANCE (kΩ-1)

PWM FREQUENCY (kHz)

0.0350.0250.015

150

200

250

300

350

400

450

500

550

100

0.005 0.045

200Hz DIMMING OPERATION

MAX16816 toc17

2ms/div

10%

DIMMING

1A/div

50%

DIMMING

1A/div

90%

DIMMING

1A/div

LED CURRENT DUTY CYCLE

vs. DIM VOLTAGE

MAX16816 toc18

DIM VOLTAGE (V)

LED CURRENT DUTY CYCLE (%)

100

0 3

DRIVER DRV RISE TIME

vs. DRI VOLTAGE

MAX16816 toc19

DRI VOLTAGE (V)

DRV RISE TIME (ns)

131197

5 15

5nF CAPACITOR CONNECTED

FROM DRV TO AGND

DRIVER DRI FALL TIME

vs. DRI VOLTAGE

MAX16816 toc20

DRI VOLTAGE (V)

DRV FALL TIME (ns)

131197

5 15

5nF CAPACITOR CONNECTED

FROM DRV TO AGND

REF VOLTAGE

vs. TEMPERATURE

MAX16816 toc13

TEMPERATURE (°C)

REF VOLTAGE (V)

11590-35 -10 15 40 65

2.98

3.00

3.02

3.04

3.06

3.08

3.10

3.12

2.96

-60 140

IREF = 100µA

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

Maxim Integrated

│

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Typical Operating Characteristics (continued)

PIN NAME FUNCTION

1, 24 N.C. No Connection. Not internally connected.

2 UVEN

Undervoltage Lockout (UVLO) Threshold/Enable Input. UVEN is a dual-function adjustable UVLO threshold

input with an enable feature. Connect UVEN to VCC through a resistive voltage-divider to program the UVLO

threshold. Connect UVEN directly to VCC to use the 5.9V (max) default UVLO threshold. Apply a voltage

greater than 1.244V to UVEN to enable the device.

3 REG1

5V Regulator Output. REG1 is an internal low-dropout voltage regulator that generates a 5V (VCC > 6V)

output voltage and supplies power to internal circuitry. Bypass REG1 to AGND through a 1µF ceramic

capacitor.

4 AGND Analog Ground. Use proper single-point ground design and decoupling to avoid ground impedance loop

errors.

5 REF Accurate 3V Buffered Reference Output. Connect REF to DIM through a resistive voltage-divider to apply a

DC voltage for analog-controlled dimming functionality. Leave REF unconnected if unused.

6 DIM

Dimming Control Input. Connect DIM to an external PWM signal for PWM dimming. For analog-controlled

dimming, connect DIM to REF through a resistive voltage-divider. The dimming frequency is 200Hz under

these conditions. Connect DIM to AGND to turn off the LEDs.

7 RTSYNC

Sync Input/Output. The internal PWM clock is selectable through the RTOF EEPROM bit. Connect an

external resistor to RTSYNC and set the RTOF register to ‘0’ to select a clock frequency between 125kHz

and 500kHz. Set RTOF register to ‘0’ and connect RTSYNC to an external clock to synchronize the device

with external clock. Set RTOF register to ‘1’ to use the xed 125kHz oscillator. Under these conditions,

RTSYNC is powered off and may be left in any state. See the Oscillator, Clock, and Synchronization section.

8 CLKOUT Clock Output. CLKOUT buffers the oscillator/clock. Connect CLKOUT to the SYNC input of another device

to operate the MAX16816 in a multichannel conguration. CLKOUT is a logic output.

9, 10, 11 I.C. Internally Connected. Must be connected to AGND.

12 COMP Error-Amplier Output. Connect the compensation network from COMP to FB for stable closed-loop control.

Use low-leakage ceramic capacitors in the feedback network.

13 CS

Current-Sense Voltage Output. CS outputs a voltage proportional to the current sensed through the current-

sense amplier. Connect CS through a passive network to FB as dictated by the chosen compensation

scheme.

14 FB Error-Amplier Inverting Input

15 OV

Overvoltage Protection Input. Connect OV to HI through a resistive voltage-divider to set the overvoltage limit

for the load. When the voltage at OV exceeds the 1.235V (typ) threshold, an overvoltage fault is generated

and the switching MOSFET turns off. The MOSFET is turned on again when the voltage at OV drops below

1.17V (typ).

16, 17 SGND Switching Ground. SGND is the ground for non-analog and high-current gate-driver circuitry.

18 DRV Gate-Driver Output. Connect DRV through a series resistor to the gate of an external n-channel MOSFET to

reduce EMI. DRV can sink 1A or source 0.5A.

19 DRI Gate-Driver Supply Input. Connect DRI to REG2 to power the primary switching MOSFET driver.

20 SNS+ Positive Peak Current-Sense Input. Connect SNS+ to the positive side of the switch current-sense resistor,

RSENSE.

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

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Pin Description

PIN NAME FUNCTION

21 SNS- Negative Peak Current-Sense Input. Connect SNS- to the negative side of the switch current-sense resistor,

RSENSE.

22 QGND Analog Ground. Ensure a low-impedance connection between QGND and AGND.

23 DGT Dimming Gate-Driver Output. Connect DGT to the gate of an external n-channel MOSFET for dimming. DGT

is powered by the internal regulator, CLAMP, and is referenced to LO.

25 LO

Low-Voltage Input. LO is the return point for the LED current. When using the MAX16816 in a buck-boost

conguration, connect LO to VCC. When using the device in a boost conguration only, connect LO to

AGND. Connect LO to the junction of the inductor and LED current-sense resistor, RCS, when using a buck

conguration.

26 CS+ Noninverting Current-Sense Amplier Input. Connect CS+ to the positive side of an external sense resistor,

RCS, connected in series with the load (LEDs).

27 CS- Inverting Current-Sense Amplier Input. Connect CS- to the negative side of an external sense resistor, RCS,

connected in series with the load (LEDs).

28 CLMP

Internal CLAMP Regulator Bypass. CLAMP supplies an 8V (typ) output when VHI ≥ 9V. If VHI is lower

than 9V, VCLMP is one diode drop below VHI. The CLAMP regulator powers the current-sense amplier

and provides the high reference for the dimming driver. VCLMP must be at least 2.5V higher than VLO to

enable the current-sense amplier and dimming MOSFET driver. Bypass CLMP to LO with a 0.1µF ceramic

capacitor.

29 HI High-Voltage Input. HI is referred to LO. HI supplies power to the current-sense amplier and dimming

MOSFET gate driver through the CLMP regulator.

30 REG2

Internal Regulator Output. REG2 is an internal voltage regulator that generates EEPROM-programmable

(5V to 15V) output and supplies power to internal circuitry. Connect REG2 to DRI to power the switching

MOSFET driver during normal operation. Bypass REG2 to AGND with a 10µF ceramic capacitor.

31 VCC Supply Voltage Input

32 FAULT

FAULT Input/Output. FAULT is a bidirectional high-voltage logic input/output. FAULT multiplexes a 1-Wire

programming interface with a fault indicator. FAULT is internally pulled up to 5V through a 10kΩ resistor and

a 1.8mA (max) current pulldown to ground.

EP EP Exposed Pad. Connect EP to AGND. EP also functions as a heatsink to maximize thermal dissipation. Do not

use as the main ground connection.

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

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Pin Description (continued)

Functional Diagram

BLANKING

TIME

200Hz

SGND

15V

REG2

COMP

UVLO

AND

DGT

DRIVER

UVEN

DIM

DRV

SNS-

PWM

EAMP

COMP

OVP

REG1

POR

REF

BUF

DDR

QGND

REG1

DRI

FAULT

CLAMP

D-I

SOFT-START

D-I

ILIM

-200mV

HIC

-300mV

AGND 200mV

SLOPE

CS- CS+

CSA

REG2

SNS+

CLMP

3.0V

UGB

CMP

-1.3 x V

OSC

RTSYNC

CLKOUT

OSC

CONTROL

BLOCK

SLOPE

COMP

1-Wire

INTERFACE

SLOPE

CLMP

THERMAL

SHUTDOWN

800mV

MAX16816

REG2 DRIVER

D-I

D-I BLANKING

D-I

0.926V

BINNING

INDICATES A USER-PROGRAMMABLE EEPROM FEATURE

BINNING

REG2 DRIVER

TRIM REGISTERS

BLANKING

SLOPE COMP

SOFT-START

RTOSCSEL

D-I

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

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Detailed Description

The MAX16816 is a current-mode PWM LED driver for

use in driving HB LEDs. An output current accuracy of

5% is achievable using two current-regulation loops: one

current-regulation loop controls the external switching

MOSFET peak current through a sense resistor (RSENSE)

from SNS+ to SNS- while the other current-regulation loop

controls the average LED string current through the sense

resistor, RCS, in series with the LEDs.

The MAX16816 provides LED binning through one

programmable on-chip nonvolatile EEPROM. The LED

current can be scaled up to a factor of 1.6. This feature is

used to offset factory LED luminance variations and allows

the system to achieve overall luminance accuracy.

A programmable undervoltage lockout (UVEN) ensures

predictable operation during brownout conditions. The

UVEN input circuitry monitors the supply voltage (VCC)

and turns the driver off when VCC drops below the UVLO

threshold. Connect UVEN to VCC to use the 5.7V (typ)

default UVLO threshold. The MAX16816 includes a cycle-

by-cycle current limit that turns off the gate drive to the

external switching MOSFET (QS) during an overcurrent

condition and a programmable oscillator that simplifies

and optimizes the design of external magnetics.

The MAX16816 is capable of synchronizing to an external

clock or operating in a stand-alone mode. A single resistor

(RT) can be used to adjust the switching frequency from

125kHz to 500kHz for stand-alone operation. To synchro-

nize the device with an external clock, apply a clock signal

directly to the RTSYNC input. A buffered clock output,

CLKOUT, is available to configure the MAX16816 for mul-

tichannel applications.

The external RT oscillator can be disabled by setting

EEPROM register RTOF to ‘1’. The MAX16816 provides

wide contrast pulsed dimming (up to 1000:1) utilizing a

separate dimming input. Apply either a DC level voltage or

low-frequency PWM signal to the dimming input. DC level

input results in a 200Hz fixed dimming frequency.

The MAX16816 provides configurable on-chip nonvolatile

EEPROM features including a programmable soft-start,

load current, external MOSFET gate-driver supply voltage,

blanking time, and slope compensation.

Protection features include peak current limiting, HICCUP

mode current limiting, output overvoltage protection, short-

circuit protection, and thermal shutdown. The HICCUP

current-limit circuitry reduces the power delivered to the

load during severe fault conditions. A nonlatching overvolt-

age protection limits the voltage on the external switching

MOSFET (QS) under open-circuit conditions in the LED

string. During continuous operation at high input voltages,

the power dissipation of the MAX16816 could exceed

the maximum rating and the internal thermal shutdown

circuitry safely turns off the MAX16816 when the device

junction temperature exceeds +165°C. When the junction

temperature drops below the hysteresis temperature, the

MAX16816 automatically reinitiates startup.

Undervoltage Lockout/Enable (UVEN)

The MAX16816 features a dual-purpose adjustable under-

voltage lockout input and enable function (UVEN). Connect

UVEN to VCC through a resistive voltage-divider to set

the undervoltage-lockout (UVLO) threshold. The device is

enabled when the voltage at UVEN exceeds the 1.244V

(typ) threshold. Drive UVEN to ground to disable the output.

Setting the UVLO Threshold

Connect UVEN directly to VCC to select the default 5.7V

(typ) UVLO threshold. Connect UVEN to VCC through

a resistive voltage-divider to select a UVLO threshold

(Figure 1). Select the desired UVLO threshold voltage,

VUVLO, and calculate resistor values using the following

equation:

UVEN

UV1 UV2 UVLO UVEN

R R x

V - V







where RUV1 + RUV2 ≤ 270kΩ. VUVEN is the 1.244V (typ)

UVEN threshold voltage.

The capacitor CUVEN is required to prevent chattering at

the UVLO threshold due to line impedance drops during

power-up and dimming. If the undervoltage setting is very

close to the required minimum operating voltage, there can

Figure 1. Setting the UVLO Threshold

MAX16816

VCC

UVEN

QGND

RUV2

RUV1

CUVEN

VIN

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

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be large jumps in the voltage at VCC during dimming, which

may cause the MAX16816 to turn on and off when the

dimming signal transitions from low to high. The capacitor

CUVEN should be large enough to limit the ripple on UVEN

to less than the 100mV (min) UVEN hysteresis so that the

device does not turn off under these circumstances.

Soft-Start

The MAX16816 features a digitally programmable soft-start

delay that allows the load current to ramp up in a controlled

manner, minimizing output overshoot. Soft-start begins

once the device is enabled and VCC exceeds the UVLO

threshold. Soft-start circuitry slowly increases the internal

soft-start voltage (VSS), resulting in a controlled rise of

the load current. Signals applied to DIM are ignored until

the soft-start duration is complete and a successive delay

of 200μs has elapsed. Use the Digital Soft-Start Duration

from 0 (no delay) to 4.096ms. See the EEPROM and

Programming section for more information on using the

Digital Soft-Start Duration register.

Regulators (REG1, REG2, CLAMP)

The MAX16816 includes a fixed 5V voltage regulator, REG1;

an EEPROM-adjustable regulator, REG2; and an internal

8V regulator, CLAMP. REG1 and REG2 power up when

VCC exceeds the UVLO threshold. REG1 supplies power to

internal circuitry and remains on during PWM dimming.

REG1 is capable of driving external loads up to 2mA.

Use the REG2 Control Register in the EEPROM to select

an output voltage from 5V to 15V for REG2. Connect

REG2 to DRI to generate the supply voltage for the

primary switching MOSFET driver, DRV. REG2 is capable

of delivering up to 20mA of current. See the EEPROM and

Programming section for more information on configuring

the REG2 output voltage.

CLAMP is powered by HI and supplies power to the

current-sense amplifier (CSA). CSA is enabled when

VCLMP goes 2.5V above VLO and is disabled when

(VCLMP - VLO) falls below 2.28V. The CLAMP regulator

also provides power to the dimming MOSFET control

circuitry. CLMP is the output of the CLAMP regulator. Do

not use CLMP to power external circuitry. Bypass CLMP

to LO with a 0.1μF ceramic capacitor. A larger capacitor

will result in overshoot of the load current.

Reference Voltage Output (REF)

The MAX16816 includes a 5% accurate, 3V (typ) buffered

reference output, REF. REF is a push-pull output capable

of sourcing/sinking up to 200μA of current and can drive

a maximum load capacitance of 100pF. Connect REF

to DIM through a resistive voltage-divider to supply an

analog signal for dimming. See the Dimming Input (DIM)

section for more information.

Dimming MOSFET Driver (DDR)

The MAX16816 requires an external n-channel MOSFET

for PWM dimming. Connect the MOSFET to the output of

the DDR dimming driver (DGT) for normal operation. VDGT

swings between VLO and VCLMP. The DDR dimming driver

is capable of sinking or sourcing up to 20mA of current. The

average current required to drive the dimming MOSFET

(IDRIVE_DIM) depends on the MOSFET’s total gate charge

(QG_DIM) and the dimming frequency of the converter,

fDIM. Use the following equation to calculate the supply

current for the n-channel dimming FET driver.

IDRIVE_DIM = QG_DIM x fDIM

n-Channel MOSFET Switch Driver (DRV)

The MAX16816 drives an external n-channel MOSFET

for switching. Use an external supply or connect REG2

to DRI to power the MOSFET driver. The driver output,

VDRV, swings between ground and VDRI. Ensure that

VDRI remains below the absolute maximum VGS rating

of the external MOSFET. DRV is capable of sinking 2A

or sourcing 1.4A of peak current, allowing the MAX16816

to switch MOSFETs in high-power applications. The

average current sourced to drive the external MOSFET

depends on the total gate charge (QG) and operating

frequency of the converter (fSW). The power dissipation

in the MAX16816 is a function of the average output drive

current (IDRIVE). Use the following equations to calculate

the power dissipation in the gate-driver section of the

MAX16816 due to IDRIVE:

IDRIVE = QG x fSW

PD = IDRIVE x VDRI

where VDRI is the supply voltage to the gate driver.

Dimming Input (DIM)

The dimming input, DIM, functions with either analog or

PWM control signals. Once the internal pulse detector

detects three successive edges of a PWM signal with

a frequency between 80Hz and 2kHz, the MAX16816

synchronizes to the external signal and pulse-width

modulates the LED current at the external DIM input

frequency with the same duty cycle as the DIM input.

If an analog control signal is applied to DIM, the MAX16816

compares the DC input to an internally generated 200Hz

ramp to pulse-width modulate the LED current (fDIM =

200Hz). The output current duty cycle is linearly adjust-

able from 0 to 100% (0.2V < VDIM < 2.8V).

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

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Use the following formula to calculate voltage (VDIM)

necessary for a given output current duty cycle (D):

VDIM = (D x 2.6) + 0.2V

where VDIM is the voltage applied to DIM in volts.

Connect DIM to REF through a resistive voltage-divider to

apply a DC DIM control signal (Figure 2). Use the required

dimming input voltage (VDIM) calculated above and select

appropriate resistor values using the following equation:

R4 = R3 x VDIM/(VREF - VDIM)

where VREF is the 3V reference output voltage and 15kΩ

≤ R3 + R4 ≤ 150kΩ.

A minimum 20μs pulse width is necessary for proper

operation during dimming.

Oscillator, Clock, and Synchronization

The MAX16816 is capable of stand-alone operation, of

synchronizing to an external clock, and of driving external

devices in SYNC mode. For stand-alone operation, set the

EEPROM Oscillator Enable/Disable (RTOF) bit to ‘1’ to use

the fixed internal 125kHz oscillator or set RTOF to ‘0’ and

program the switching frequency by connecting a single

external resistor (RT) between RTSYNC and ground. Select

a switching frequency (fSW) between 125kHz and 500kHz

and calculate RT using the following formula:

TSW

500kHz

R 25k

= ×Ω

where the switching frequency is in kHz and RT is in kΩ.

To synchronize the MAX16816 with an external clock

signal ranging from 125kHz to 500kHz, set the RTOF bit

to ‘0’ and connect the clock signal to the RTSYNC input.

The MAX16816 synchronizes to the clock signal after the

detection of 5 successive clock edges at RTSYNC.

A buffered clock output, CLKOUT, can drive the RTSYNC

input of an external PWM controller for multichannel applica-

tions. CLKOUT can drive capacitive loads up to 500pF.

If the PWM switching frequency is set to 125kHz, the

RTSYNC oscillator can be temporarily disabled by setting

the EEPROM RTOF bit to ‘1’. In this case, the internal

125kHz frequency-fixed oscillator drives the PWM. See the

EEPROM and Programming section for more information

on setting the Oscillator Enable/Disable bit in the EEPROM.

Multichannel Conguration

The MAX16816 is capable of multichannel operation and

is configurable as a master or slave in a Master-Slave

configuration, or in a Peer-to-Peer configuration. Connect

CLKOUT to the SYNC input of an external device to

use the MAX16816 as a master clock signal. Connect

an external clock signal to RTSYNC to configure the

MAX16816 as a slave. To setup two MAX16816 devices

in a daisy-chain configuration, drive the RTSYNC input

of one MAX16816 with the CLKOUT buffer of another

(Figure 3).

ILIM and HICCUP Comparator

RSENSE sets the peak current through the inductor for

switching. The differential voltage across RSENSE is

compared to the 200mV voltage-trip limit of the current-

limit comparator, ILIM. Set the current limit 20% higher

than the peak switch current at the rated output power

and minimum voltage. Use the following equation to

calculate RSENSE:

RSENSE = VSENSE/(1.2 x IPEAK)

where VSENSE is the 200mV maximum differential volt-

age between SNS+ and SNS- and IPEAK is the peak

inductor current at full load and minimum input voltage.

When the voltage drop across RSENSE exceeds the

ILIM threshold, the MOSFET driver (DRV) terminates the

Figure 2. Creating DIM Input Signal from REF

Figure 3. Master-Slave/Peer-Peer Clock Configuration

MAX16816

REF

AGND

DIM MAX16816 MAX16816

RTSYNC CLKOUT RTSYNC CLKOUT

MASTER/PEER SLAVE/PEER

MAX16816 Programmable Switch-Mode LED Driver

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on-cycle and turns the switch off, reducing the current

through the inductor. The FET is turned back on at the

beginning of the next switching cycle.

When the voltage across RSENSE exceeds the 300mV

(typ) HICCUP threshold, the HIC comparator terminates

the on-cycle of the device, turning the switching MOSFET

off. Following a startup delay of 8ms (typ), the MAX16816

reinitiates soft-start. The device will continue to operate in

HICCUP mode until the overcurrent condition is removed.

A programmable built-in leading-edge blanking circuit

of the current-sense signal prevents these comparators

from prematurely terminating the on-cycle of the external

switching MOSFET (QS). Select a blanking time from

75ns to 150ns by configuring the Blanking Time register

in the EEPROM. In some cases, the maximum blanking

time may not be adequate and an additional RC filter may

be required to prevent spurious turn-off.

Load Current Sense

The load current-sense resistor (RCS) monitors the

current through the LEDs. The internal floating current-

sense amplifier (CSA) measures the differential voltage

across RCS, and generates a voltage proportional to the

load current through RCS at CS. This voltage on CS is

referred to AGND. The closed loop regulates the load

current to a value (ILED) given by the following equation:

ILED = VSS/RCS

where VSS is the binning adjustment voltage. Set the

value of VSS in the Binning Adjustment register in

the EEPROM between 100mV and 166mV. See the

EEPROM and Programming section for more information

on adjusting the binning voltage.

Slope Compensation

The amount of slope compensation required is largely

dependent on the down-slope of the inductor current when

the switching MOSFET (QS) is off. The inductor down-slope

depends on the input-to-output voltage differential of the

converter, the inductor value, and the switching frequency.

For stability, the compensation slope should be equal to

or greater than half of the inductor current down-slope

multiplied by the current-sense resistance (RSENSE).

See the EEPROM and Programming section for more

information on the ESLP register.

Internal Voltage-Error Amplier (EAMP)

The MAX16816 includes a built-in voltage amplifier, with

three-state output, which can be used to close the feedback

loop. The buffered output current-sense signal appears at

CS, which is connected to the inverting input (FB) of the

error amplifier through resistor R1. The noninverting input

is connected to an internally trimmed current reference.

The output of the error amplifier is controlled by the signal

applied to DIM. When DIM is high, the output of the ampli-

fier is connected to COMP. The amplifier output is open

when DIM is low. This enables the integrating capacitor

to hold the charge when the DIM signal has turned off the

gate drive. When DIM is high again, the voltage on the

compensation capacitors (C1 and C2) forces the converter

into steady state almost instantaneously.

PWM Dimming

PWM dimming is achieved by driving DIM with either a

PWM signal or a DC signal. The PWM signal is connected

internally to the error amplifier, the dimming MOSFET

gate driver, and the switching MOSFET gate driver. When

the DIM signal is high, the dimming MOSFET and the

switching MOSFET drivers are enabled and the output

of the voltage-error amplifier is connected to the external

compensation network. Also, the buffered current-sense

signal is connected to CS. Preventing discharge of the

compensation capacitor when the DIM signal is low

allows the control loop to return the LED current to its

original value almost instantaneously.

When the DIM signal goes low, the output of the error

amplifier is disconnected from the compensation network

and the compensation capacitors (C1 and C2) voltage is

preserved. Choose low-leakage capacitors for C1 and C2.

The drivers for the external dimming and switching MOSFETs

are disabled, and the converter stops switching. The inductor

energy is now transferred to the output capacitors.

When the DIM signal goes high and the gate drivers are

enabled, the additional voltage on the output capacitor

may cause a current spike on the LED string. A larger

output capacitor will result in a smaller current spike. If

the overcurrent spike exceeds 30% of the programmed

LED current, the dimming is turned off and the MAX16816

reinitiates soft-start.

FAULT 1-Wire Interface

The MAX16816 features a FAULT output multiplexed

with a 1-Wire programming interface. Once the voltage

at UVEN exceeds the UVLO threshold, the device is

enabled and FAULT will pulse low once, indicating the

beginning of the programming window. Two programming

mode entry codes must be entered within 8ms after the

pulse to enter programming mode (see Table 1). The

MAX16816 will register the second entry code only after

the first code has been received. Once the MAX16816

successfully enters programming mode, the data and

clock for the 1-Wire interface are supplied through FAULT.

MAX16816 Programmable Switch-Mode LED Driver

with Analog-Controlled PWM Dimming

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Once the programming window has passed, the EEPROM

is no longer accessible without cycling power to the

device. Under these conditions, FAULT will go low only

when a fault (overvoltage, overcurrent, or HICCUP mode)

occurs or when the supply voltage drops below the UVLO

threshold.

EEPROM and Programming

Nonvolatile EEPROM is available to configure the

MAX16816 through a 1-Wire serial interface. Registers

are located in a linear address space as shown in

Table 2. All other EEPROM locations are reserved.

Configure the six control registers to adjust param-

eters including the REG2 voltage, soft-start durations,

blanking time, LED load current (binning), slope compen-

sation, and to enable/disable the RTOF oscillator. See the

1-Wire Interface section for more information about

1-Wire programming.

Binning-Adjustment Register (BIN)

The MAX16816 uses a feedback loop to control the load

current. The differential voltage across the current-sense

resistor (RCS) is compared with an internal adjustable

reference to regulate the LED current. The voltage across

Table 1. Programming Mode Entry Codes

Table 2. EEPROM Memory Map

PROGRAMMING MODE

ENTRY CODE D7 D6 D5 D4 D3 D2 D1 D0 HEX

CODE

PASS_CODE_1 0 0 1 0 1 0 0 1 29h

PASS_CODE_2 0 0 0 0 1 0 0 1 09h

EEPROM

ADDRESS

RANGE

NO. OF

BITS TYPE DESCRIPTION

Binning Adjustment (BIN) 24h–27h 4 R/W Adjusts the LED current.

REG2 Control (DRPS) 28h–2Bh 4 R/W Sets the output voltage for REG2. Connect REG2 to DRI

to supply the high-side voltage for the gate driver, DRV.

Blanking Time Adjustment

(BLNK) 32h–33h 2 R/W Adjusts the blanking time for debouncing.

Digital Soft-Start Duration (SS) 34h–36h 2 R/W

Adjusts the soft-start duration to allow the load current

to ramp up in a controlled manner, minimizing output

overshoot.

Internal Oscillator Enable/Disable

(RTOF) 37h 1 R/W Enables/disables the internal oscillator for stand-alone

operation or to synchronize with an external clock.

Slope Compensation (ESLP) 38h–3Bh 4 R/W Adjusts the slope compensation for stability.

MAX16816 Programmable Switch-Mode LED Driver

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the sense resistor is measured differentially to achieve

high immunity to common-mode noise. The MAX16816

includes a factory-set regulation voltage of 133mV ±3%

across RCS. Adjust the differential regulation voltage by

programming the binning adjustment register (see Table 3).

The reference voltage level may not necessarily be equal

to the regulation voltage. There are offsets involved that

are trimmed at the factory. Read the default register code

and step up the code by one to increase the regulation

voltage by 6.66mV. Step down the code by one to reduce

the regulation voltage by 6.66mV.

REG2 Control Register (DRPS)

REG2 is EEPROM configurable to supply a voltage

ranging from 5V to 15V and is capable of sourcing up to

20mA. Connect REG2 to the primary switching MOSFET

gate-driver supply input, DRI, for normal operation.

Adjust REG2 by programming the REG2 Control Register.

See Table 4.

Blanking Time-Adjustment Register (BLNK)

The MAX16816 features a programmable blanking time to

mask out the current-sense signal for a short duration to

avoid the ILIM and HICCUP comparators from prematurely

terminating the on-cycle of the switching MOSFET. This

blanking time allows for higher input current during startup

without triggering a fault condition. The blanking time is

adjustable in the range of 150ns to 75ns by configuring the

EEPROM. See Table 5.

Table 3. Binning Adjustment Register

Table 4. REG2 Control Register

Table 5. Blanking Time

*Factory default.

REFERENCE

VOLTAGE LEVEL

(mV)

EEPROM ADDRESS

27h 26h 25h 24h

100.00 0 0 0 0

106.67 0 0 0 1

113.33 0 0 1 0

120.00 0 0 1 1

126.67 0 1 0 0

133.33 0 1 0 1

140.00 0 1 1 0

146.67 0 1 1 1

153.33 1 0 0 0

160.00 1 0 0 1

166.67 1 0 1 0

173.33* 1 0 1 1

180.00* 1 1 0 0

186.67* 1 1 0 1

193.33* 1 1 1 0

200.00* 1 1 1 1

*Not recommended.

REG2 OUTPUT

VOLTAGE

(V)

EEPROM ADDRESS

2Bh 2Ah 29h 28h

5.000 0 0 0 0

5.667 0 0 0 1

6.333 0 0 1 0

7.000* 0 0 1 1

7.667 0 1 0 0

8.333 0 1 0 1

9.000 0 1 1 0

9.667 0 1 1 1

10.333 1 0 0 0

11.000 1 0 0 1

11.667 1 0 1 0

12.333 1 0 1 1

13.000 1 1 0 0

13.667 1 1 0 1

14.333 1 1 1 0

15.000 1 1 1 1

BLANKING TIME

(ns)

EEPROM ADDRESS

33h 32h

150* 0 0

125 0 1

100 1 0

75 1 1

*Factory default

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Digital Soft-Start Duration Register (SS)

The MAX16816 programmable soft-start feature allows the

load current to ramp up in a controlled manner, eliminating

output overshoot during startup. Soft-start begins once the

device is enabled and VCC has exceeded the 5.5V (min)

rising threshold voltage. Adjust the soft-start duration by

configuring the EEPROM. Enter ‘111’ to disable the soft-

start feature. See Table 6.

Oscillator Enable/Disable Register (RTOF)

The MAX16816 features a programmable accurate

RTSYNC oscillator and resistor synchronized to an

external clock. Set the EEPROM bit RTOF to ‘1’ to disable

the external sync mode, and the RTSYNC oscillator, and to

use the fixed internal frequency of 125kHz as the switching

frequency. Set RTOF to ‘0’ to synchronize with an external

oscillator or to program the external oscillator frequency

with an external resistor, RT. See Table 7.

Slope Compensation Register (ESLP)

The MAX16816 uses an internally generated ramp to

stabilize the current loop when operating at duty cycles

above 50%. Set the compensating slope by adjusting the

peak ramp voltage through the on-chip EEPROM. See

Tables 8 and 9.

Table 8. Slope Compensation with Clock

Generated by RT Oscillator

Table 9. Slope Compensation with

External Clock Applied to RTSYNC or RT

Oscillator Off

Table 6. Digital Soft-Start Duration

Table 7. Oscillator Enable/Disable

*Factory default.

*Factory default

DURATION

(µs)

EEPROM ADDRESS

36h 35h 34h

4096* 0 0 0

2048 0 0 1

1860 0 1 0

1024 0 1 1

768 1 0 0

512 1 0 1

256 1 1 0

No SS 1 1 1

RT OSCILLATOR EEPROM ADDRESS

37h

RT Oscillator Off 1

RT Oscillator On* 0

SLOPE

COMPENSATION

(mV/clock cycle)

EEPROM ADDRESS

3Bh 3Ah 39h 38h

0 0 0 0 0

20 0 0 0 1

40 0 0 1 0

60 0 0 1 1

80 0 1 0 0

100 0 1 0 1

120* 0 1 1 0

140 0 1 1 1

160 1 0 0 0

180 1 0 0 1

200 1 0 1 0

220 1 0 1 1

240 1 1 0 0

260 1 1 0 1

280 1 1 1 0

300 1 1 1 1

SLOPE

COMPENSATION

(mV/µs)

EEPROM ADDRESS

3Bh 3Ah 39h 38h

0 0 0 0 0

2 0 0 0 1

4 0 0 1 0

6 0 0 1 1

8 0 1 0 0

10 0 1 0 1

12* 0 1 1 0

14 0 1 1 1

16 1 0 0 0

18 1 0 0 1

20 1 0 1 0

22 1 0 1 1

24 1 1 0 0

26 1 1 0 1

28 1 1 1 0

30 1 1 1 1

MAX16816 Programmable Switch-Mode LED Driver

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Fault Protection

The MAX16816 features built-in overvoltage protection, over-

current protection, HICCUP mode current-limit protection,

and thermal shutdown. Overvoltage protection is achieved

by connecting OV to HI through a resistive voltage-divider.

HICCUP mode limits the power dissipation in the external

MOSFETs during severe fault conditions. Internal thermal

shutdown protection safely turns off the converter when the

IC junction temperature exceeds +165°C.

Overvoltage Protection

The overvoltage-protection (OVP) comparator compares

the voltage at OV with a 1.235V (typ) internal reference.

When the voltage at OV exceeds the internal reference,

the OVP comparator terminates PWM switching and no

further energy is transferred to the load. The MAX16816

reinitiates soft-start once the overvoltage condition is

removed. Connect OV to HI through a resistive voltage-

divider to set the overvoltage threshold at the output.

Setting the Overvoltage Threshold

Connect OV to HI or to the high-side of the LEDs through

a resistive voltage-divider to set the overvoltage threshold

at the output (Figure 4). The overvoltage protection (OVP)

comparator compares the voltage at OV with a 1.235V

(typ) internal reference. Use the following equation to

calculate resistor values:

OV_LIM OV

OV1 OV2 OV

V V

R R x

−







where VOV is the 1.235V OV threshold. Choose ROV1

and ROV2 to be reasonably high-value resistors to prevent

discharge of filter capacitors. This will prevent unnecessary

undervoltage and overvoltage conditions during dimming.

Load-Dump Protection

The MAX16816 features load-dump protection up to 76V.

LED drivers using the MAX16816 can sustain single fault

load dump events. Repeated load dump events within

very short time intervals can cause damage to the dim-

ming MOSFET due to excess power dissipation.

Thermal Shutdown

The MAX16816 contains an internal temperature sen-

sor that turns off all outputs when the die temperature

exceeds +165°C. Outputs are enabled again when the die

temperature drops below +145°C.

Applications Information

Inductor Selection

The minimum required inductance is a function of

operating frequency, input-to-output voltage differential,

and the peak-to-peak inductor current (ΔIL). Higher

ΔIL allows for a lower inductor value while a lower ΔIL

requires a higher inductor value. A lower inductor value

minimizes size and cost, improves large-signal transient

response, but reduces efficiency due to higher peak cur-

rents and higher peak-to-peak output ripple voltage for

the same output capacitor. On the other hand, higher

inductance increases efficiency by reducing the ripple

current, ΔIL. However, resistive losses due to extra turns

can exceed the benefit gained from lower ripple current

levels, especially when the inductance is increased with-

out also allowing for larger inductor dimensions. A good

compromise is to choose ΔIL equal to 30% of the full load

current. The inductor saturating current is also important

to avoid runaway current during the output overload and

continuous short circuit. Select the ISAT to be higher than

the maximum peak current limit.

Buck configuration: In a buck configuration the average

inductor current does not vary with the input. The worst-

case peak current occurs at high input voltage. In this

case the inductance (L) for continuous-conduction mode

is given by:

( )

OUT INMAX OUT

INMAX SW L

V x V V

L V x f x I

−

=∆

where VINMAX is the maximum input voltage, fSW is the

switching frequency, and VOUT is the output voltage.

Figure 4. Setting the Overvoltage Threshold

AGND

ROV1

ROV2

VLED+

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Boost configuration: In the boost converter, the average

inductor current varies with line and the maximum aver-

age current occurs at low line. For the boost converter,

the average inductor current is equal to the input current.

In this case the inductance (L) is calculated as:

( )

INMIN OUT INMIN

OUT SW L

V x V V

L V x f x I

−

=∆

where VINMIN is the minimum input voltage, VOUT is

the output voltage, and fSW is the switching frequency.

Buck-boost configuration: In a buck-boost converter the

average inductor current is equal to the sum of the input

current and the load current. In this case the inductance,

L, is:

( )

OUT INMIN

OUT INMIN SW L

V x V

V V x f x I

+∆

where VINMIN is the minimum input voltage, VOUT is the

output voltage, and fSW is the switching frequency.

Output Capacitor

The function of the output capacitor is to reduce the out-

put ripple to acceptable levels. The ESR, ESL, and the

bulk capacitance of the output capacitor contribute to the

output ripple. In most of the applications, the output ESR

and ESL effects can be dramatically reduced by using

low-ESR ceramic capacitors. To reduce the ESL effects,

connect multiple ceramic capacitors in parallel to achieve

the required bulk capacitance.

In a buck configuration, the output capacitance (CF) is

calculated using the following equation:

INMAX OUT OUT

R INMAX SW

( V V ) V

V 2 L V f

−×

≥∆ ××× ×

where ΔVR is the maximum allowable output ripple.

In a boost configuration, the output capacitance (CF) is

calculated as:

OUT INMIN OUT

FR OUT SW

( V V ) 2 I

C V V f

− ××

≥∆× ×

where IOUT is the output current.

In a buck-boost configuration, the output capacitance (CF)

is calculated as:

OUT OUT

FR OUT INMIN SW

2 V I

C V ( V V ) f

××

≥∆× + ×

where VOUT is the voltage across the load and IOUT is

the output current.

Input Capacitor

An input capacitor connected between VCC and ground

must be used when configuring the MAX16816 as a buck

converter. Use a low-ESR input capacitor that can handle

the maximum input RMS ripple current. Calculate the maxi-

mum allowable RMS ripple using the following equation:

OUT OUT INMIN OUT

IN(RMS) INMIN

I V ( V - V )

I V

××

In most of the cases, an additional electrolytic capacitor

should be added to prevent input oscillations due to line

impedances.

When using the MAX16816 in a boost or buck-boost config-

uration, the input RMS current is low and the input capaci-

tance can be small (see the Typical Operating Circuits).

Operating the MAX16816 Without the

Dimming Switch

The MAX16816 can also be used in the absence of

the dimming MOSFET. In this case, the PWM dimming

performance is compromised but in applications that do

not require dimming the MAX16816 can still be used. A

short circuit across the load will cause the MAX16816 to

disable the gate drivers and they will remain off until the

input power is recycled.

Switching Power MOSFET Losses

When selecting MOSFETs for switching, consider the total

gate charge, power dissipation, the maximum drain-to-

source voltage, and package thermal impedance. The

product of the MOSFET gate charge and RDS(ON) is a figure

of merit, with a lower number signifying better performance.

Select MOSFETs optimized for high-frequency switching

applications.

Layout Recommendations

Typically, there are two sources of noise emission in a

switching power supply: high di/dt loops and high dv/dt

surfaces. For example, traces that carry the drain current

often form high di/dt loops. Similarly, the heatsink of the

MOSFET connected to the device drain presents a high

dv/dt source; therefore, minimize the surface area of

the heatsink as much as possible. Keep all PCB traces

carrying switching currents as short as possible to mini-

mize current loops. Use ground planes for best results.

MAX16816 Programmable Switch-Mode LED Driver

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Careful PCB layout is critical to achieve low switching

losses and clean, stable operation. Use a multilayer

board whenever possible for better noise performance

and power dissipation. Follow these guidelines for good

PCB layout:

●Use a large copper plane under the MAX16816 pack-

age. Ensure that all heat-dissipating components have

adequate cooling. Connect the exposed pad of the de-

vice to the ground plane.

●Isolate the power components and high current paths

from sensitive analog circuitry.

●Keep the high-current paths short, especially at the

ground terminals. This practice is essential for stable,

jitter-free operation. Keep switching loops short.

●Connect AGND, SGND, and QGND to a ground plane.

Ensure a low-impedance connection between all

ground points.

●Keep the power traces and load connections short. This

practice is essential for high efficiency. Use thick copper

PCBs (2oz vs. 1oz) to enhance full-load efficiency.

●Ensure that the feedback connection to FB is short

and direct.

●Route high-speed switching nodes away from the

sensitive analog areas.

●To prevent discharge of the compensation capacitors (C1

and C2) during the off-time of the dimming cycle, ensure

that the PCB area close to these components has ex-

tremely low leakage. Discharge of these capacitors due

to leakage may result in degraded dimming performance.

1-Wire Interface

EEPROM implementation uses a 1-Wire communication

method. A 1-Wire net-based system consists of three main

elements: a bus master with controlling software, the wiring

and associated connectors, and 1-Wire devices. Data on

the 1-Wire net is transferred with respect to time slots. For

example, the master pulls the bus low and holds it for 15μs

or less to write a logic ‘1’, and holds the bus low for at least

60μs to write a logic ‘0’. During EEPROM programming the

MAX16816 is a 1-Wire slave device only. Data and clock

signals are supplied through FAULT.

MAX16816 1-Wire Function Commands

Table 10 shows the list of 1-Wire function commands for the

MAX16816. Use these commands to start the programming

mode, write to the on-chip EEPROM, and read EEPROM

through the 1-Wire interface.

PASS_CODE_ONE: The PASS_CODE_ONE sequence

is the first code that the MAX16816 must receive from the

master. PASS_CODE_ONE must be received within the

initial 8ms programming window after startup.

PASS_CODE_TWO: The PASS_CODE_TWO sequence

is the second code that the MAX16816 must receive

during the 8ms programming window. The MAX16816

will start searching for PASS_CODE_TWO only after

PASS_CODE_ONE has been received.

EXT_EEM_MODE: The EXT_EEM_MODE command

clears the PASS_CODE_ONE and PASS_CODE_TWO

verification register. Use this command to exit program-

ming mode.

SET_WRITE_EE: The SET_WRITE_EE command is

the write all command for the MAX16816. When the

device detects the SET_WRITE_EE command the write

sequence begins. All EEPROM bits are copied to the

EEPROM from the scratchpad with a single SET_WRITE_

EE command. This command also sets an internal BUSY

flag to mask all other incoming signals.

SET_WRITE_SCH: The SET_WRITE_SCH command

transfers data to the scratchpad. The 4 MSBs contain the

ten. The internal BUSY flag is not set by this command. Table

Table 10. MAX16816 1-Wire Function Commands

COMMAND DATA BIT CODE HEX

CODE

D7 D6 D5 D4 D3 D2 D1 D0

PASS_CODE_ONE 0 0 1 0 1 0 0 1 29h

PASS_CODE_TWO 0 0 0 0 1 0 0 1 09h

EXT_EEM_MODE 0 0 0 0 0 0 0 1 01h

SET_WRITE_EE 0 0 0 0 0 1 0 0 04h

SET_WRITE_SCH ADD ADD ADD ADD DATA DATA DATA DATA —

SET_READ_SCH 0 0 0 0 0 1 1 0 06h

MAX16816 Programmable Switch-Mode LED Driver

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11 shows the MAX16816 EEPROM memory organization.

Use the SET_WRITE_EE command to transfer data from the

scratchpad to the EEPROM.

SET_READ_SCH: The SET_READ_SCH command is

the command to read data in the scratch pad buffer.

Once the MAX16816 receives the SET_READ_SCH

command, data on the scratchpad register is shifted

out. After 60 clock cycles, the MAX16816 completes the

SET_READ_SCH sequence. The BUSY signal is not set

by this command.

Programming

To program the MAX16816 on-chip EEPROM with a

pulldown device, directly connect FAULT to the DATA IN

input of a microcontroller (μC). Also, connect FAULT to

the DATA OUT output of a μC using an external switch

(Figure 5). Connect the EN of the μC directly to UVEN to

control the internal timer of the MAX16816 for programming

purposes. Ensure that VCC is greater than the UVLO

threshold because both UVEN and FAULT are pulled up to

5V. See the Electrical Characteristic tables for details.

Programming Sequences

The μC (master) starts the communication with the

MAX16816 by pulling UVEN high. The MAX16816 then

does the handshaking with the μC by pulling FAULT low.

Once the μC receives the handshaking signal, it begins

the initialization sequences to reset the 1-Wire interface.

The sequence consists of a reset pulse from the μC

followed by a presence pulse from the MAX16816. At this

point the μC must send PASS_CODE_ONE and PASS_

CODE_TWO. These pass codes must be received by the

MAX16816 within the 8ms programming slot to allow the

MAX16816 to enter the EE programming mode.

1-Wire Signaling

The MAX16816 requires strict protocols to ensure data

integrity. The protocol consists of four types of signal-

ing on one line: reset sequence with Reset Pulse and

Presence Pulse, Write-Zero, Write-One, and Read-Data.

Table 11. MAX16816 Memory Map (Scratchpad)

Figure 5. Programming Through a FAULT Pin

SCRATCHPAD

ADDRESS EEPROM ADDRESS REGISTER

1h Reserved Reserved

2h Reserved Reserved

3h Reserved Reserved

4h Reserved Reserved

5h Reserved Reserved

6h–9h 14h–23h Reserved

Ah 24h–27h Binning-Adjustment register

Bh 28h–2Bh REG2 Control register

Ch 2Ch–2Fh Reserved

Dh 30h–33h Blanking Time-Adjustment register

Eh 34h–37h Digital Soft-Start Duration register, Internal Oscillator Enable bit

Fh 38h–3Bh Slope-Compensation register

MAX16816

VCC

FAULT

READ

WRITE

DATA IN

DATA OUT

UVEN

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Except for the Presence Pulse, the bus master initiates

all falling edges.

Externally pull FAULT below VIL to indicate a logic-input

low. Release the pulldown device to indicate a logic-input

high. The MAX16816 will pull FAULT low below VOL to

indicate a logic-output low. FAULT is pulled high with

an internal 10kΩ resistor above VOH to indicate a logic-

output high.

Initialization Procedure (Reset and Presence

Pulses)

All 1-Wire communication with the MAX16816 begins

with an initialization sequence that consists of a Reset

Pulse from the master followed by a Presence Pulse from

the MAX16816 (Figure 6). When the MAX16816 sends

the Presence Pulse in response to the Reset Pulse, it

is indicating to the master that it is ready to receive and

transmit data.

During the initialization sequence, the bus master

transmits the reset pulse by pulling the 1-Wire bus low

for a minimum of 480μs. The bus master then releases

the bus and goes into receive mode. When the bus is

released, the pullup resistor pulls the 1-Wire bus high.

When the MAX16816 detects this rising edge, it waits

15μs to 60μs and then transmits a Presence Pulse by

pulling the 1-Wire bus low for 60μs to 240μs.

Read and Write Time Slots

The bus master writes data to the MAX16816 during write

time slots and reads data from the MAX16816 during read

time slots. One bit of data is transmitted over the 1-Wire

bus per time slot.

Figure 6. 1-Wire Initialization Timing

tRSTL

MASTER Tx "RESET PULSE" MASTER Rx "PRESENCE PULSE"

VOH

VOL OR VIL

tMSP

RESISTOR MASTER MAX16816

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Write Time Slots

There are two types of write time slots: Write-1 time slots

and Write-0 time slots. The bus master uses a Write-1

time slot to write a logic ‘1’ to the MAX16816 and a Write-

0 time slot to write a logic ‘0’. All write time slots must be

a minimum of 60μs in duration, with a minimum of a 1μs

recovery time between individual Write slots. Both types

of write time slots are initiated by the master pulling the

1-Wire bus low (Figures 7 and 8).

To generate a Write-1 time slot, the bus master must

release the 1-Wire bus within 15μs after pulling the bus

low. When the bus is released, the pullup resistor will pull

the bus high. To generate a Write-0 time slot, the bus

master must continue to hold the bus low for the duration

of the time slot (at least 60μs) after pulling the 1-Wire bus

low. The MAX16816 samples the 1-Wire bus during a win-

dow that lasts from 15μs to 60μs after the master initiates

the Write time slot. If the bus is high during the samples

window, a ‘1’ is written to the MAX16816. If the line is low,

a ‘0’ is written to the MAX16816.

Figure 7. 1-Wire Write-1 Time Slot

Figure 8. 1-Wire Write-0 Time Slot

RESISTOR MASTER

tW1L

tREC

tSLOT

VOH

VOL

MAX16816

SAMPLING

WINDOW

RESISTOR MASTER

VOH

VIL

tW0L

tREC

tSLOT

MAX16816

SAMPLING

WINDOW

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Read Time Slots

The MAX16816 can only transmit data to the master

when the master issues read time slots.

All read time slots must be a minimum of 60μs in duration

with a minimum of a 1μs recovery time between slots. A

read time slot is initiated by the master device pulling the

1-Wire bus low for a minimum of 1μs and then releasing

it (Figure 9). After the master initiates the read time slot,

the MAX16816 will transmit a ‘1’ or a ‘0’ on the bus. The

MAX16816 transmits a ‘1’ by leaving the bus high and

transmits a ‘0’ by pulling the bus low. When transmitting

a ‘0’, the MAX16816 will release the bus before the end

of the time slot, and the bus will be pulled back to its

high idle state by the pullup resistor. Output data from

the MAX16816 is valid for 15μs after the falling edge that

initiated the read time slot. Therefore, the master must

release the bus and then sample the bus state within

15μs from the start of the slot.

Figure 9. 1-Wire Read Time Slot

RESISTOR MASTER MAX16816

tREC

tSLOT

tRL

tMSR

MASTER

SAMPLING

WINDOW

VOH

VIL / VOL

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VIN

RCS

RUV2

DRV

DRI

VCC

SNS+

QGND

RTSYNC

CS-

CS+ LO

COMP

REG2

DGT

UVEN

SNS-

AGNDREG1

RSENSE

ROV1

ROV2

CLMP

SGND

CCLMP

CREG2

CREG1

LEDs

RUV1

CUVEN

FAULT

REF

DIM

MAX16816

BOOST CONFIGURATION

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Typical Operating Circuits (continued)

VIN

RCS

CREG1

RUV2

DRV

REG2

VCC

SNS+

QGND

RTSYNC

CS-

HI LO

COMP DRI

UVEN

FAULT

SNS-

AGND

RSENSE

CLMP

SGND

CCLMP

CREG2

LEDs

BUCK CONFIGURATION

RUV1

CUVEN

MAX16816

REG1

DIM

CS+ DGT

DIM

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Typical Operating Circuits (continued)

Package Information

For the latest package outline information and land patterns

(footprints), go to www.maximintegrated.com/packages. Note

that a “+”, “#”, or “-” in the package code indicates RoHS status

only. Package drawings may show a different suffix character, but

the drawing pertains to the package regardless of RoHS status.

PACKAGE

TYPE

PACKAGE

CODE

OUTLINE

NO.

LAND

PATTERN NO.

32 TQFN-EP T3244M+4 21-0140 90-0014

Chip Information

PROCESS: BiCMOS

32 31 30 29 28 27 26

9 10 11 12 13 14 15

MAX16816

TQFN

(5mm x 5mm)

TOP VIEW

UVEN

N.C.

REG1

AGND

REF

DIM

RTSYNC

CLKOUT

FAULT

VCC

REG2

CLMP

CS-

CS+

N.C.

DGT

QGND

SNS-

SNS+

DRI

DRV

17 SGND

SGND

COMP

I.C.

*EP

*EP = EXPOSED PAD

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Pin Conguration

Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses

are implied. Maxim Integrated reserves the right to change the circuitry and specications without notice at any time. The parametric values (min and max limits)

shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.

Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.

MAX16816 Programmable Switch-Mode LED Driver

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Revision History

REVISION

NUMBER

REVISION

DATE DESCRIPTION PAGES

CHANGED

0 1/08 Initial release —

1 4/15

No /V OPNs; removed automotive references in General Description, Applications,

and Detailed Description sections; added Package Thermal Characteristics section

with new Note 1 and renumbered remaining numbers in Electrical Characteristics

1, 2–10, 15

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.