© 1995 Microchip Technology Inc.

DS70010I-page 1

FEATURES

• Drives up to 32 LCD segments of arbitrary config-

uration

• CMOS process for: wide supply voltage range,

low- power operation, high-noise immunity, wide

temperature range

• CMOS and TTL-compatible inputs

• Electrostatic discharge protection on all pins

• Cascadable

• On-chip oscillator

• Requires only three control lines

APPLICATIONS

• Industrial displays

• Consumer product displays

• Telecom product displays

• Automotive dashboard displays

DESCRIPTION

The AY0438 is a CMOS integrated device that drives a

liquid crystal display, usually under microprocessor

control. The part acts as a smart peripheral that drives

up to 32 LCD segments. It needs only three control

lines due to its serial input construction. It latches the

data to be displayed and relieves the microprocessor

from the task of generating the required waveforms.

The AY0438 can drive any standard or custom parallel

drive LCD display, whether it be field effect or dynamic

scattering; 7-, 9-, 14- or 16-segment characters; deci-

mals; leading + or -; or special symbols. Several

AY0438 devices can be cascaded. The AC frequency

of the LCD waveforms can either be supplied by the

user or generated by attaching a capacitor to the LCD

input, which controls the frequency of an internal oscil-

lator.

The AY0438 is available in 40-lead dual in-line plastic

and 44-lead PLCC packages. Unpackaged dice are

also available.

PIN CONFIGURATION

CLOCK

SEG 1

SEG 2

SEG 3

DATA OUT

DATA IN

SEG 4

SEG 5

LCD

Φ

BP

SEG 6

SEG 7

SEG 8

SEG 9

SEG 10

SEG 11

SEG 12

SEG 13

SEG 14

LOAD

SEG 32

SEG 31

SEG 30

SEG 29

SEG 28

SEG 27

SEG 26

SEG 25

SEG 24

SEG 23

SEG 22

SEG 21

SEG 20

SEG 19

SEG 18

SEG 17

SEG 16

SEG 15

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

40

39

38

37

36

35

34

33

32

31

30

29

28

27

26

25

24

23

22

21

NC

DATA OUT

DATA IN

SEG 4

SEG 5

LCD

Φ

BP

SEG 6

SEG 7

SEG 8

NC

SEG 29

SEG 28

SEG 27

SEG 26

SEG 25

SEG 24

SEG 23

SEG 22

SEG 21

SEG 20

SEG 19

7

8

9

10

11

12

13

14

15

16

17

39

38

37

36

35

34

33

32

31

30

29

40-Lead Dual In-line

44 PLCC

AY0438

AY0438

32-Segment CMOS LCD Driver