Technical Note

9/14

BU9795AKV,BU9795AFV,BU9795AGUW,BU9794AKV,BU97950FUV

www.rohm.com

2011.03 - Rev.A

© 2011 ROHM Co., Ltd. All rights reserved.

LCD

BIAS

SELECTOR

common

driver

Segment

driver

OSCILLATOR

Power On Reset

SD

SCL

VSS

OSCIN

VSS

COM0……COM3

SEG0……SEG49

IF FILTER

serial inter face

Command

register

common

counter

DDRAM

LCD voltage generator

Command

Data Decoder

blink timing

generator

＋

－

＋

－

VLCD

CSB

TEST1

INHb

VDD

TEST2

SEG38

SEG21

SEG39

SEG20

SEG40

SEG19

SEG41

SEG18

SEG42

SEG17

SEG43

SEG16

SEG44

SEG15

SEG45

SEG14

SEG46

SEG13

SEG47

SEG12

SEG48

SEG11

SEG49

SEG10

COM0

SEG9

COM1

SEG8

COM2

SEG7

COM3

SEG6

49

64

32

17

<BU9794AKV>

●Block Diagram

●Pin Arrangement

Fig.10 Block Diagram (BU9794AKV)

Fig.11 Pin Arrangement (BU9794AKV)

●Terminal Description

Terminal

Terminal No.

I/O

Function

INHb

8

I

Input terminal for turn off display

H: turn on display, L: turn off display

TEST1

9

I

Test input (ROHM use only)

Must be connect to VSS

TEST2

10

I

Test input (ROHM use only)

Must be connect to VSS

OSCIN

4

I

External clock input

Ex clock and Int clock can be changed by command.

Must be connect to VSS when use internal oscillation circuit.

SD

7

I

serial data input

SCL

6

I

serial data transfer clock

CSB

5

I

Chip select : “L” active

VSS

3

-

GND

VDD

2

-

Power supply

VLCD

1

-

Power supply for LCD driving

SEG0-49

11-60

O

SEGMENT output for LCD driving

COM0-3

61-64

O

COMMON output for LCD driving