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
buffer
A0
A8
Column
address buffer
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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 37 36 35
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
x 16 bits
512
512x16
Sense ampllfler I/O gate
512
Column decoder
Pre-decoder
Figure 52 BLOCK DIAGRAM OF IC
– 52 –
Function
34 33 32 31 30 29 28 27 26 25
Clock generator No. 3
Lower byte Upper byte
Data input buffer
I/O1 to I/O8 I/O9 to I/O16
Data output buffer
I/O1 to I/O8 I/O9 to I/O16
Substrate bias generator
24 23
VCC
VSS
WE
I/O1
I/O16
OE