Datasheet

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General Description

The MAX16809 is an integrated, high-efficiency white

or RGB LED driver. It is designed for LCD backlighting

and other LED lighting applications with multiple strings

of LEDs. The MAX16809’s current-mode PWM control-

ler regulates the necessary voltage to the LED array.

Depending on the input voltage and LED voltage range,

this device can be used with boost or buck-boost (SEPIC)

topologies.

The MAX16809 LED driver includes 16 open-drain,

constant-current-sinking LED driver outputs rated for

36V continuous operation. The LED current-control cir-

cuitry achieves ±3% current matching among strings

and enables paralleling of outputs for LED string cur-

rents higher than 55mA. The output-enable pin is used

for simultaneous PWM dimming of all output channels.

Dimming frequency range is 50Hz to 30kHz and dimming

ratio is up to 5000:1. The constant-current outputs are

single resistor programmable and the LED current can be

adjusted up to 55mA per output channel.

The MAX16809 operates either in stand-alone mode or

with a microcontroller (µC) using an industry-standard,

4-wire serial interface.

The MAX16809 includes overtemperature protection,

operates over the full -40°C to +125°C temperature range,

and is available in a 5mm x 7mm thermally enhanced,

38-pin TQFN exposed pad package.

Features

● 16 Constant-Current Output Channels (Up to 55mA

Each)

● ±3% Current Matching Among Outputs

● Paralleling Channels Allows Higher Current per LED

String

● Outputs Rated for 36V Continuous Voltage

● Output-Enable Pin for PWM Dimming (Up to 30kHz)

● One Resistor Sets LED Current for All Channels

● Wide Dimming Ratio Up to 5000:1

● Low Current-Sense Reference (300mV) for High

Efficiency

● 8V to 26.5V Input Voltage or Higher with External

Biasing Devices

● 4-Wire Serial Interface to Control Individual Output

Channels

Applications

● LCD White or RGB LED Backlighting:

LCD TVs, Desktop, and Notebook Panels

Industrial and Medical Displays

● Ambient, Mood, and Accent Lighting

19-0656; Rev 3; 4/14

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

*EP = Exposed pad.

PART TEMP RANGE PIN-PACKAGE

MAX16809ATU+ -40°C to +125°C 38 TQFN-EP*

OUT0

OUT1

OUT2

OUT3

OUT4

OUT5

OUT6

OUT7

SET

DIN

PGND

V+

DOUT

CLK

REF

RTCT

REF

SET

BYP

OUT CS AGND COMP

OUT

3V TO 5.5V

OUT

LEDs

STAND-ALONE OPERATION

MAX16809

OUT8

OUT9

OUT10

OUT11

OUT12

OUT13

OUT14

OUT15

MAX16809 Integrated 16-Channel LED Driver with

Switch-Mode Boost and SEPIC Controller

Typical Operating Circuits continued at end of data sheet.

Typical Operating Circuits

Pin Configuration appears at end of data sheet.

Ordering Information

EVALUATION KIT AVAILABLE

Summary of content (20 pages)

PAGE 1
EVALUATION KIT AVAILABLE MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller General Description The MAX16809 is an integrated, high-efficiency white or RGB LED driver. It is designed for LCD backlighting and other LED lighting applications with multiple strings of LEDs. The MAX16809’s current-mode PWM controller regulates the necessary voltage to the LED array.
PAGE 2
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Absolute Maximum Ratings VCC to AGND.........................................................-0.3V to +30V Current into VCC (VCC > 24V)............................................30mA V+ to PGND.............................................................-0.3V to +6V OUT to AGND............................................ -0.3V to (VCC + 0.3V) OUT Current (10µs duration).................................................
PAGE 3
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Electrical Characteristics (PWM Controller) (continued) (VCC = +15V, V+ = +3V to +5.5V referenced to PGND, RT = 10kΩ, CT = 3.3nF, REF = open, COMP = open, CREF = 0.1µF, VFB = 2V, CS = AGND, AGND = PGND = 0V; all voltages are measured with respect to AGND, unless otherwise noted. TJ = TA = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.
PAGE 4
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Electrical Characteristics (LED Driver) (V+ = +3V to +5.5V, AGND = PGND = 0V; all voltages are measured with respect to PGND, unless otherwise noted. TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER Operating Supply Voltage Output Voltage SYMBOL CONDITIONS V+ MIN TYP 3.0 VOUT_ _ MAX UNITS 5.
PAGE 5
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller 5V Timing Characteristics (V+ = +4.5V to +5.5V, AGND = PGND = 0V; all voltages are measured with respect to PGND, unless otherwise noted. TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.
PAGE 6
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller 3.3V Timing Characteristics (V+ = +3V to < +4.5V, AGND = PGND = 0V; all voltages are measured with respect to PGND, unless otherwise noted. TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.
PAGE 7
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Typical Operating Characteristics (VCC = +15V, V+ = 3V to 5.5V, RT = 10kΩ, CT = 3.3nF, VREF = COMP = open, CREF = 0.1µF, VFB = 2V, CS = AGND = PGND = 0V. Typical values are at TA = +25°C, unless otherwise noted.) 8 37 VCC FALLING 6 5 4 3 2 HYSTERESIS 1 4.7 33 4.5 4.3 31 4.1 29 3.9 27 3.7 3.
PAGE 8
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Typical Operating Characteristics (VCC = +15V, V+ = 3V to 5.5V, RT = 10kΩ, CT = 3.3nF, VREF = COMP = open, CREF = 0.1µF, VFB = 2V, CS = AGND = PGND = 0V. Typical values are at TA = +25°C, unless otherwise noted.) 1 0.24 0.22 0.1 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (°C) ISINK = 200mA 8 6 5 4 3 2 1M RDS_ON (Ω) 10M TEMPERATURE (°C) PROPAGATION DELAY FROM CURRENT-LIMIT COMPARATOR TO OUT vs.
PAGE 9
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Typical Operating Characteristics (VCC = +15V, V+ = 3V to 5.5V, RT = 10kΩ, CT = 3.3nF, VREF = COMP = open, CREF = 0.1µF, VFB = 2V, CS = AGND = PGND = 0V. Typical values are at TA = +25°C, unless otherwise noted.) TA = +85°C 3.60 TA = +25°C TA = -40°C 3.55 45 40 TA = +85°C TA = +125°C 35 30 25 TA = +25°C 20 3.5 4.0 4.5 5.0 5.5 TA = -40°C 3.0 3.5 SUPPLY CURRENT vs.
PAGE 10
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Typical Operating Characteristics (VCC = +15V, V+ = 3V to 5.5V, RT = 10kΩ, CT = 3.3nF, VREF = COMP = open, CREF = 0.1µF, VFB = 2V, CS = AGND = PGND = 0V. Typical values are at TA = +25°C, unless otherwise noted.) TA = +25°C TA = +85°C 30 TA = +125°C 20 10 0 0 0.5 1.0 1.5 2.0 2.5 TA = +25°C MAX16809 toc26 TA = +85°C 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) www.maximintegrated.com 3.5 4.0 4.5 5.0 5.
PAGE 11
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Pin Description PIN NAME 1, 31, 32, 36, 38 N.C. 2 FB 3 COMP 4–11 FUNCTION No Connection. Not internally connected. Leave unconnected. Error-Amplifier Inverting Input Error-Amplifier Output OUT8–OUT15 LED Driver Outputs. OUT8–OUT15 are open-drain, constant-current-sinking outputs rated for 36V. Active-Low, Output Enable Input. Drive OE low to PGND to enable the OUT0–OUT15. Drive OE high to disable OUT0–OUT15.
PAGE 12
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller cathode of a string of LEDs connected in series. The constant-current capability is up to 55mA per output, set for all 16 outputs by an external resistor, RSET. The device can operate in a stand-alone mode (see the Typical Operating Circuits). The number of channels can be expanded by using the MAX6970 and MAX6971 family in conjunction with the MAX16809. UVLO REFERENCE 2.5V VOLTAGEDIVIDER PREREG 5V VCC 26.
PAGE 13
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller V+ 68W/L 1.23V W/L MAX16809 OUT_ _ 1.23 REST 945R R SET PGND Figure 1b. OUT_ _ Driver Internal Diagram Switch-Mode Controller Current-Mode Control Loop The advantages of current-mode control over voltage-mode control are twofold. First, there is the feed-forward characteristic brought on by the controller's ability to adjust for variations in the input voltage on a cycle-bycycle basis.
PAGE 14
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller The oscillator frequency is then: fOSC = RCS = 1 t + ( C tD) Reference Output REF is a 5V reference output that can source 20mA. Bypass REF to AGND with a 0.1µF capacitor. Current Limit The MAX16809 includes a fast current-limit comparator to terminate the ON cycle during an overload or a fault condition.
PAGE 15
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller LED Driver LE is the latch-enable input of the MAX16809 that transfers data from the 16-bit shift register to its 16-bit output latches (transparent latch). The data latches on the falling edge of LE (Figure 4). The fourth input (OE) provides output-enable control of the output drivers. When OE is driven high, the outputs (OUT0–OUT15) are forced to high impedance without altering the contents of the output latches.
PAGE 16
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller LE tLW tCL tCH tLS tCP CLK tDS tDH D15 DIN D14 D1 D0 tDO D15 DOUT tOEW OE tOEF 80% OUT_ _ tOER 20% tF tR Figure 3. 4-Wire Serial-Interface Timing Diagram LE tLRF OUT_ _ LE tLRR OUT_ _ CLK The MAX16809 uses an external resistor, RSET, to set the LED current for outputs OUT0–OUT15. The minimum allowed value of RSET is 311Ω, which sets the output currents to 55mA.
PAGE 17
MAX16809 Stand-Alone Operation In stand-alone operation, the MAX16809 does not use the 4-wire interface (see the Typical Operating Circuits). Connect DIN and LE to V+ and provide at least 16 external clock pulses to CLK to enable 16 output ports. This startup pulse sequence can be provided either using an external clock or the PWM signal. The external clock can also be generated using the signal at RTCT and an external comparator.
PAGE 18
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Typical Operating Circuits (continued) VIN L VOUT D LEDs COUT R1 CC2 RCS CC1 RC1 R2 OUT CS AGND COMP VCC FB CIN 3V TO 5.5V V+ OUT0 PGND OUT2 OUT1 CBYP OUT3 OUT4 MAX16809 OUT5 OUT6 SCLK MOSI µC MISO LOAD ENABLE OUT7 OUT8 CLK DIN DOUT LE OE OUT9 OUT10 OUT11 OUT12 OUT13 OUT14 SET RTCT REF OUT15 OPERATION WITH MICROCONTROLLER RT RSET CREF www.maximintegrated.
PAGE 19
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller PROCESS: BiCMOS LE OUT0 OUT1 OUT2 OUT3 OUT4 OUT5 Chip Information OUT6 OUT7 RTCT N.C. TOP VIEW CS Pin Configuration 31 30 29 28 27 26 25 24 23 22 21 20 N.C. 32 19 CLK AGND 33 18 DIN OUT 34 17 PGND VCC 35 16 PGND MAX16809 N.C. 36 15 V+ 4 5 6 7 8 9 OUT8 OUT9 OUT10 OUT11 OUT12 OUT13 10 11 12 OE 3 OUT15 2 OUT14 1 COMP 13 DOUT + FB 14 SET N.C. 38 N.C.
PAGE 20
MAX16809 Integrated 16-Channel LED Driver with Switch-Mode Boost and SEPIC Controller Revision History REVISION NUMBER REVISION DATE PAGES CHANGED 0 10/06 Initial release 1 3/07 Released the MAX16810 on the data sheet. 2 8/09 Removed the MAX16810 from the data sheet.