MAX6954_09 Datasheet, PDF (1/39 Pages) Maxim Integrated Products – 4-Wire Interfaced, 2.7V to 5.5V LED Display Driver with I/O Expander and Key Scan

19-2460; Rev 4; 3/09
4-Wire Interfaced, 2.7V to 5.5V LED Display
Driver with I/O Expander and Key Scan
General Description
The MAX6954 is a compact display driver that inter-
faces microprocessors to a mix of 7-segment, 14-seg-
ment, and 16-segment LED displays through an SPI™-
or QSPI™-compatible 4-wire serial interface. The serial
interface may be cascaded through multiple devices.
The MAX6954 drives up to 16 digits 7-segment, 8 digits
14-segment, 8 digits 16-segment, or 128 discrete
LEDs, while functioning from a supply voltage as low as
2.7V. The driver includes five I/O expander (or GPIO)
lines, some or all of which may be configured as a key-
switch reader, which automatically scans and
debounces a matrix of up to 32 switches.
Included on chip are full 14- and 16-segment ASCII
104-character fonts, a hexadecimal font for 7-segment
displays, multiplex scan circuitry, anode and cathode
drivers, and static RAM that stores each digit. The max-
imum segment current for the display digits is set using
a single external resistor. Digit intensity can be inde-
pendently adjusted using the 16-step internal digital
brightness control. The MAX6954 includes a low-power
shutdown mode, a scan-limit register that allows the
user to display from 1 to 16 digits, segment blinking
(synchronized across multiple drivers, if desired), and a
test mode, which forces all LEDs on. The LED drivers
are slew-rate limited to reduce EMI.
For a 2-wire interfaced version, refer to the MAX6955
data sheet. An evaluation kit (EV kit) for the MAX6955 is
available.
Applications
Set-Top Boxes
Panel Meters
Automotive
Bar Graph Displays
White Goods
Audio/Video Equipment
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX6954AAX
-40°C to +125°C
36 SSOP
MAX6954APL
-40°C to +125°C
40 PDIP
MAX6954ATL+
-40°C to +125°C
40 TQFN-EP*
+Denotes a lead-free/RoHS-compliant package.
*EP = Exposed pad.
Pin Configurations and Typical Operating Circuits appear
at end of data sheet.
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
Features
♦ High-Speed 26MHz SPI/QSPI/MICROWIRE™-
Compatible Serial Interface
♦ 2.7V to 5.5V Operation
♦ Drives Up to 16 Digits 7-Segment, 8 Digits
14-Segment, 8 Digits 16-Segment, 128 Discrete
LEDs, or a Combination of Digit Types
♦ Drives Common-Cathode Monocolor and Bicolor
LED Displays
♦ Built-In ASCII 104-Character Font for 14-Segment
and 16-Segment Digits and Hexadecimal Font for
7-Segment Digits
♦ Automatic Blinking Control for each Segment
♦ 10µA (typ) Low-Power Shutdown (Data Retained)
♦ 16-Step Digit-by-Digit Digital Brightness Control
♦ Display Blanked on Power-Up
♦ Slew-Rate Limited Segment Drivers for Lower EMI
♦ Five GPIO Port Pins Can Be Configured as Key-
Switch Reader to Scan and Debounce Up to 32
Switches with n-Key Rollover
♦ IRQ Output when a Key Input Is Debounced
♦ 36-Pin SSOP and 40-Pin DIP and TQFN Packages
♦ Automotive Temperature Range Standard
Functional Diagram
ISET
CURRENT
SOURCE
OSC
OSC_OUT
DIVIDER/
COUNTER
NETWORK
GPIO
AND KEY-SCAN
CONTROL
PWM
BRIGHTNESS
CONTROL
DIGIT
MULTIPLEXER
P0 TO P4
LED
DRIVERS
O0 TO O23
MAX6954
CHARACTER
GENERATOR
ROM
BLINK
BLINK
CONTROL
CLK
CS
DIN
DOUT
CONFIGURATION
RAM
REGISTER
4-WIRE SERIAL INTERFACE
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.