MAX6972 Datasheet, PDF (1/23 Pages) Maxim Integrated Products – 16-Output PWM LED Drivers for Message Boards

19-0534; Rev 0; 5/06
EVAALVUAAILTAIOBNLEKIT
16-Output PWM LED Drivers
for Message Boards
General Description
The MAX6972/MAX6973 precision current-sinking,
16-output PWM LED drivers drive red, green, and/or blue
LEDs for full-color graphic message boards and video
displays. Each output has an individual 12-bit (MAX6972)
or 14-bit (MAX6973) PWM-intensity (hue) control and
7-bit (MAX6972) or 5-bit (MAX6973) global PWM intensity
(luminance) control. The MAX6972/MAX6973 also fea-
ture open-circuit LED fault-detection circuitry, as well as
a watchdog timer.
The driver has two banks of eight outputs, with each bank
intended to drive a different color in RGB applications.
The standard application uses three MAX6972/
MAX6973s to drive eight RGB LEDs. The full-scale current
for each bank of eight outputs is adjustable from 11mA
to 55mA in 256 steps (0.3125% per step) to calibrate
each color.
The MAX6972/MAX6973 can optionally multiplex by
using outputs MUX0 and MUX1, which each drive an
external pnp transistor. Multiplexing doubles the
MAX6972/MAX6973 drive capability to 32 LEDs.
The MAX6972/MAX6973 operate from a 3.0V to 3.6V
power supply. The LED power supply can range from
3V to 7V. The LED drivers require only 0.8V headroom
above the LEDs’ forward-voltage drop. Using a sepa-
rate LED supply voltage for each LED minimizes power
consumption.
The serial interface uses differential signaling for the
high-speed clock and data signals to reduce EMI and
improve signal integrity. The MAX6972/MAX6973 buffer
all interface signals to simplify cascading devices in
modules that use a large number of drivers.
An internal watchdog timer, when enabled, automatically
clears the pixel-data registers and blanks the display if
any of the signal inputs fail to toggle within 40ms.
The MAX6972/MAX6973 are available in 32-pin TQFN
packages and operate over the -40°C to +125°C
temperature range.
Refer to the MAX6974/MAX6975 data sheet for a
24-output, 6mA to 30mA software-compatible device.
EZCascade is a trademark of Maxim Integrated Products, Inc.
Applications
LED Video Display Panels
LED Message Boards
Variable Message Signs (VMS)
Signs
Graphic Panels
Typical Operating Circuit appears at the end of data sheet.
Features
♦ 16 LED Current Sink Outputs (Two Banks of Eight
Outputs)
♦ 32 LED Drive Option When Multiplexing
♦ 33MHz Clock Supports Up to 63 Frames per
Second of Video
♦ Constant Output Current Calibration from 11mA
to 55mA in 256 Steps
♦ EZCascade™ Interface Simplifies Multiple Driver
Cascading Without External Buffers
♦ 12-Bit or 14-Bit Individual PWM LED Intensity
Controls
♦ 7-Bit or 5-Bit Panel PWM-Intensity Control
♦ +3V to +7V LED Power Supply
♦ +3.0V to +3.6V Logic Supply
♦ Open-Circuit LED Fault Detection
♦ Optional Watchdog Timer Blanks Display if
Interface Fails
♦ Standard -40°C to +125°C Operating Temperature
Range
Ordering Information
PART
TEMP RANGE ^PIN-
PACKAGE
PKG
CODE
MAX6972ATJ+ -40°C to +125°C 32 TQFN-EP* T3255-5
MAX6973ATJ+ -40°C to +125°C 32 TQFN-EP* T3255-5
*EP = Exposed paddle.
+Denotes lead-free package.
Pin Configuration
TOP VIEW
24 23 22 21 20 19 18 17
Z7 25
16 Y7
Z6 26
EP*
15 Y6
Z5 27
14 Y5
Z4 28
Z3 29
Z2 30
MAX6972ATJ
MAX6973ATJ
13 Y4
12 Y3
11 Y2
Z1 31
+
Z0 32
10 Y1
9 Y0
1 2345678
*EP = EXPOSED PADDLE.
TQFN
5mm x 5mm
________________________________________________________________ Maxim Integrated Products 1
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