Rainbow Electronics MAX6981 - Manual

General Description
The MAX6981 serial-interfaced LED driver provides
eight open-drain, constant-current-sinking LED driver
outputs rated at 36V. The device operates from a 3V to
5.5V supply. The MAX6981 supply and the LEDs’ sup-
ply can power up in any order. The constant-current
outputs are programmed together up to 55mA using a
single external resistor. The MAX6981 operates with a
25Mbps, industry-standard, 4-wire serial interface.
The MAX6981 includes circuitry that automatically
detects open-circuit LEDs. Fault status is loaded into
the serial-interface shift register when LE goes high and
is automatically shifted out on DOUT when the next
data transmission is shifted in.
The MAX6981 uses the industry-standard shift-register-
plus-latch-type serial interface. The driver accepts data
shifted into an 8-bit shift register using data input DIN
and clock input CLK. Input data appears at output
DOUT eight clock cycles later to allow cascading of
multiple MAX6981s. The latch-enable input, LE, loads
the 8 bits of shift register data into an 8-bit output latch
to set which LEDs are on and which are off. The output-
enable input, OE, gates all eight outputs on and off,
and is fast enough to be used as a PWM input for LED
intensity control.
The MAX6981 is one of a family of 10 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.
Applications
Variable Message Signs
Marquee Displays
Point-of-Order Signs
Traffic Signs
Gaming Features
Architectural Lighting
Features
♦ 25Mbps Industry-Standard 4-Wire Serial Interface
at 5V
♦ 3V to 5.5V Logic Supply
♦ 8 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
♦ Reports Open-Circuit LED Faults
♦ -40°C to +125°C Temperature Range
MAX6981
8-Port, 36V Constant-Current LED Driver
with LED Fault Detection
________________________________________________________________ Maxim Integrated Products 1
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
GND V+
SET
DOUT
OE
OUT7
OUT6
OUT5
OUT4
TOP VIEW
MAX6981
TSSOP/PDIP/SSOP
DIN
CLK
OUT1
LE
OUT0
OUT2
OUT3
Pin Configuration
Ordering Information
XX-XXXX; Rev 0; 10/05
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.
PART TEMP RANGE
PIN-
PACKAGE PKG
CODE
MAX6981AUE -40°C to +125°C 16 TSSOP-EP* U16E-3
MAX6981APE -40°C to +125°C 16 PDIP A16-2
MAX69812AA -40°C to +125°C 16 SSOP P16-1
*EP = Exposed pad.