General Description

The MAX6971 serial-interfaced LED driver provides 16

open-drain, constant-current-sinking LED driver outputs

rated at 36V. The MAX6971 operates from a 3V to 5.5V

supply. The MAX6971 supply and the LEDs’ supply or

supplies can power up in any order. The constant-cur-

rent outputs are programmed together to up to 55mA

using a single external resistor. The MAX6971 operates

with a 25Mb, industry-standard, 4-wire serial interface.

The MAX6971 uses the industry-standard, shift-register-

plus-latch-type serial interface. The driver accepts data

shifted into a 16-bit shift register using data input DIN

and clock input CLK. Input data appears at the DOUT

output 16 clock cycles later to allow cascading of multi-

ple MAX6971s. The latch-enable input, LE, loads the 16

bits of shift register data into a 16-bit output latch to set

which LEDs are on and which are off. The output-

enable, OE, gates all 16 outputs on and off, and is fast

enough to be used as a PWM input for LED intensity

control.

For applications requiring LED fault detection, refer to

the MAX6983*, which automatically detects open-circuit

LEDs.

For safety-related applications requiring a watchdog

timer, refer to the MAX6983, which includes a fail-safe

feature that blanks the display if the serial interface

becomes inactive for more than 1s.

The MAX6971 is one of a family of 12 shift-register-plus-

latch-type LED drivers. The family includes 8-port and

16-port types, with 5.5V- or 36V-rated LED outputs, with

and without open-circuit LED detection and watchdog.

All versions operate from a 3V to 5.5V supply, and are

specified over the -40°C to +125°C temperature range.

Features

♦ 25Mb, Industry-Standard, 4-Wire Serial Interface

♦ 3V to 5.5V Logic Supply

♦ 16 Constant-Current LED Outputs Rated at 36V

♦ Up to 55mA Continuous Current per Output

♦ Output Current Programmed by Single Resistor

♦ 3% Current Matching Between Outputs

♦ 6% Current Matching Between ICs

♦ High-Dissipation, 24-Pin Packages

♦ -40°C to +125°C Temperature Range

16-Port, 36V Constant-Current LED Driver

________________________________________________________________ Maxim Integrated Products

1

24

23

22

21

20

19

18

17

1

2

3

4

5

6

7

8

V+

SET

DOUT

OE

LE

CLK

DIN

GND

TOP VIEW

OUT15

OUT14

OUT13

OUT12

OUT3

OUT2

OUT1

OUT0

16

15

14

13

9

10

11

12

OUT11

OUT10

OUT9

OUT8

OUT7

OUT6

OUT5

OUT4

TSSOP/PDIP

MAX6971AUG

MAX6971ANG

Pin Configuration

Ordering Information

19-3808; Rev 0; 7/05

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Typical Application Circuit and Selector Guide appear at

end of data sheet.

Applications

Variable Message Signs

Marquee Displays

Point-of-Order Signs

Traffic Signs

Gaming Features

Architectural Lighting

PART

TEMP RANGE

PIN-PACKAGE

MAX6971AUG

-40°C to +125°C

24 TSSOP

MAX6971ANG

-40°C to +125°C

24 Narrow PDIP

*Future product—contact factory for availability.