Preliminary

AS2591

Rev. 1.0

Page 1

May 1999

Key Features

q

q 16-digit LCD driver on a 44 pin CMOS chip

q

q Operating voltage range: 3.2 to 4.8V

q

q Low power consumption: max. 150 µA

q

q Driving 7-segment displays with up to 16 digits and

12 symbols

q

q Option for 12 digits

q

q Buffer for 32 digits

q

q 4 backplanes

q

q 2-wire interface

q

q On chip timer for showing elapsed time

q

q Contrast adjustable

q

q On chip oscillator using 32.768 kHz crystal

q

q Compatible with AS2525

Block Diagramme

General Description

The AS2591 is a CMOS integrated circuit for driving a

liquid crystal display intended for use in telephones.

The driver can be used with 12- or 16-digit LCDs.

The 2-wire serial interface is compatible with the

AS2525, single-chip handsfree telephone circuit.

The device is designed for LCDs with 4 backplanes

and 24 or 31 segments providing 12 or 16 7-segment

digits and 12 symbols.

The AS2591 also includes a timer for showing

elapsed time in minutes and seconds.

The contrast can be adjusted through the serial

interface.

Package

Available in 44 pin TQFP.

SERIAL

I/F

7-

SEGMENT

DECODER

DIGIT

MEMORY

32 DIGITS

COMMAND

DECODER

BACKPLANE

COUNTER

ELAPSE

TIME

COUNTER

TIMER

POR

OSC

CONTRAST

VOLTAGE

CONTROL

4

16

16

LCD

DI

SCLK

CS

32.768 kHz

AS2591

DATA

ADDRESS

CONTROL

COM1-4

S1_n

S2_n

Figure 1: Block diagram

Austria Mikro Systeme International AG

16-Digit LCD Driver

CMOS Integrated Circuit