97
CY7C197
256Kx1 Static RAM
Features
鈥?High speed
鈥?12 ns
鈥?CMOS for optimum speed/power
鈥?Low active power
鈥?880 mW
鈥?Low standby power
鈥?220 mW
鈥?TTL-compatible inputs and outputs
鈥?Automatic power-down when deselected
vided by an active LOW Chip Enable (CE) and three-state driv-
ers. The CY7C197 has an automatic power-down feature,
reducing the power consumption by 75% when deselected.
Writing to the device is accomplished when the Chip Enable
(CE) and Write Enable (WE) inputs are both LOW. Data on the
input pin (D
IN
) is written into the memory location specified on
the address pins (A
0
through A
17
).
Reading the device is accomplished by taking chip enable
(CE) LOW while Write Enable (WE) remains HIGH. Under
these conditions the contents of the memory location specified
on the address pins will appear on the data output (D
OUT
) pin.
The output pin stays in a high-impedance state when Chip
Enable (CE) is HIGH or Write Enable (WE) is LOW.
The CY7C197 utilizes a die coat to insure alpha immunity.
Functional Description
The CY7C197 is a high-performance CMOS static RAM orga-
nized as 256K words by 1 bit. Easy memory expansion is pro-
Logic Block Diagram
DI
Pin Configurations
DIP/SOJ
Top View
INPUT BUFFER
A
13
A
14
A
15
A
16
A
17
A
0
A
1
A
2
A
3
A
4
A
0
A
1
A
2
A
3
A
4
A
5
A
6
A
7
A
8
D
OUT
WE
GND
1
24
2
23
3
22
4
21
5
20
6 7C197 19
18
7
8
17
9
16
10
15
14
11
12
13
V
CC
A
17
A
16
A
15
A
14
A
13
A
12
A
11
A
10
A
9
D
IN
CE
C197-2
CE
LCC
Top View
A2
A1
A0
V
CC
A 17
NC
A
3
A
4
A
5
A
6
A
7
A
8
D
OUT
NC
3 2 1 28 27
4
26 NC
5
25 A
16
6
24 A
15
7
23 A
14
8
7C197 22 A
13
9
21 A
12
10
20 A
11
11
19 A
10
12
18 NC
1314151617
WE
GND
CE
DIN
A9
C197-3
ROW DECODER
1024 x 256
ARRAY
SENSE AMPS
DO
COLUMN
DECODER
POWER
DOWN
A
5
A
6
A
7
A
8
A
9
A
10
A
11
A
12
WE
C197-1
Selection Guide
7C197-12
Maximum Access Time (ns)
Maximum Operating Current (mA)
Maximum Standby Current (mA)
12
150
30
7C197-15
15
140
30
7C197-20
20
135
30
7C197-25
25
95
30
7C197-35
35
95
30
30
7C197-45
45
Cypress Semiconductor Corporation
Document #: 38-05049 Rev. **
鈥?/div>
3901 North First Street
鈥?/div>
San Jose
鈥?/div>
CA 95134 鈥?408-943-2600
Revised August 24, 2001
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