Sharp CD-XP700 Service Manual page 52

CD-XP700/CD-XP7700
IC4 VHiLC32V4265B1: 4M (262144 words x 16 bits) DRAM (LC32V4265B)
Pin No. Terminal Name
1 VCC
2-5 I/O1-I/O4
6 VCC
7-10 I/O5-I/O10
11*-14* N.C.
15 WE
16 RAS
17* N.C.
18-21 A1-A3
22 VCC
23 VSS
24-28 A4-A8
29 OE
30 UCAS
31 LCAS
32*-34* N.C.
35-38 I/O9-I/O12
39 VSS
40-43 I/O13-I/O16
44 VSS
In this unit, the terminal with asterisk mark (*) is (open) terminal which is not connected to the outside.
Clock generator No. 1
RAS
UCAS
LCAS
Mode control
Refresh counter
Low address
A0
A8
Column
address buffer
Power supply.
Data I/O.
Power supply.
Data I/O.
Not used.
Write enable.
Low address strobe.
Not used.
Address input.
Power supply.
Ground
Address input.
Output enable.
Column address strobe. (Lower byte control)
Column address strobe. (Upper byte control)
Not used.
Data I/O.
Ground
Data I/O.
Ground
44 43 42 41 40 39 38
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Clock generator No. 2
262144 memory cells
512
buffer
Sense ampllfler I/O gate
Figure 52 BLOCK DIAGRAM OF IC
Function
37 36 35 34 33 32 31 30 29
Lower byte
x 16 bits
I/O1 to I/O8
I/O1 to I/O8
512x16
512
Column decoder
Pre-decoder
– 52 –
28 27 26 25 24 23
Clock generator No. 3
Upper byte
Data input buffer
I/O9 to I/O16
Data output buffer
I/O9 to I/O16
Substrate bias generator
VCC
VSS
WE
I/O1
I/O16
OE