General Description

The MAX6956 compact, serial-interfaced LED display

driver/I/O expander provide microprocessors with up to

28 ports. Each port is individually user configurable to

either a logic input, logic output, or common-anode

(CA) LED constant-current segment driver. Each port

configured as an LED segment driver behaves as a

digitally controlled constant-current sink, with 16 equal

current steps from 1.5mA to 24mA. The LED drivers are

suitable for both discrete LEDs and CA numeric and

alphanumeric LED digits.

Each port configured as a general-purpose I/O (GPIO)

can be either a push-pull logic output capable of sink-

ing 10mA and sourcing 4.5mA, or a Schmitt logic input

with optional internal pullup. Seven ports feature config-

urable transition detection logic, which generates an

interrupt upon change of port logic level. The MAX6956

is controlled through an I

interface, and uses four-level logic to allow 16 I

addresses from only 2 select pins.

The MAX6956AAX and MAX6956ATL have 28 ports

and are available in 36-pin SSOP and 40-pin thin QFN

packages, respectively. The MAX6956AAI and

MAX6956ANI have 20 ports and are available in 28-pin

SSOP and 28-pin DIP packages, respectively.

For an SPI-interfaced version, refer to the MAX6957

data sheet. For a lower cost pin-compatible port

expander without the constant-current LED drive capa-

bility, refer to the MAX7300 data sheet.

Applications

Set-Top Boxes

Bar Graph Displays

Panel Meters

Industrial Controllers

White Goods

System Monitoring

Automotive

Features

o 2.5V to 5.5V Operation

o -40°C to +125°C Temperature Range

o 20 or 28 I/O Ports, Each Configurable as

Constant-Current LED Driver

Push-Pull Logic Output

Schmitt Logic Input

Schmitt Logic Input with Internal Pullup

o 11µA (max) Shutdown Current

o 16-Step Individually Programmable Current

Control for Each LED

o Logic Transition Detection for Seven I/O Ports

2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or

28-Port LED Display Driver and I/O Expander

________________________________________________________________ Maxim Integrated Products

1

28

27

26

25

24

23

22

21

20

19

18

17

16

15

1

2

3

4

5

6

7

8

9

10

11

12

13

14

V+

AD1

SCL

SDA

P31

P30

P22

P29

P28

P27

P26

P25

P24

P23

P21

P20

P19

P18

P17

P16

P15

P14

P13

P12

AD0

GND

GND

ISET

SSOP/DIP

TOP VIEW

MAX6956

Pin Configurations

19-2414; Rev 2; 11/03

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 Operating Circuit appears at end of data sheet.

Ordering Information

PART

TEMP RANGE

PIN-PACKAGE

MAX6956ANI

-40

°C to +125°C

28 DIP

MAX6956AAI

-40

°C to +125°C

28 SSOP

MAX6956AAX

-40

°C to +125°C

36 SSOP

MAX6956ATL

-40

°C to +125°C

40 Thin QFN

or one of its sublicensed Associated Companies, conveys a

Pin Configurations continued at end of data sheet.