Rainbow Electronics MAX6971 - Manual

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
MAX6971
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.