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CY7C197 Datasheet, PDF (1/10 Pages) Cypress Semiconductor – 256Kx1 Static RAM
97
CY7C197
Features
• High speed
— 12 ns
• CMOS for optimum speed/power
• Low active power
— 880 mW
• Low standby power
— 220 mW
• TTL-compatible inputs and outputs
• Automatic power-down when deselected
Functional Description
The CY7C197 is a high-performance CMOS static RAM orga-
nized as 256K words by 1 bit. Easy memory expansion is pro-
256Kx1 Static RAM
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 (DIN) is written into the memory location specified on
the address pins (A0 through A17).
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 (DOUT) 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.
Logic Block Diagram
Pin Configurations
INPUT BUFFER
A13
A14
A15
A16
A17
A0
1024 x 256
A1
ARRAY
A2
A3
A4
COLUMN
DECODER
POWER
DOWN
DI
DIP/SOJ
Top View
LCC
Top View
A0 1
24 VCC
A1 2
A2 3
23 A17
22 A16
3 2 1 28 27
NC 4
26 NC
A3 4
21 A15
A3 5
25 A16
A4 5
20 A14
A4 6
24 A15
DO
A5 6 7C197 19 A13
A6 7
18 A12
A7 8
17 A11
A8 9
16 A10
A5
A6
A7
A8
DOUT
7
8 7C197
9
10
11
23 A14
22 A13
21 A12
20 A11
19 A10
DOUT 10
15 A9
NC 12
18 NC
WE 11
14 DIN
1314151617
GND 12
13 CE
C197-2
C197-3
CE
A5 A6 A7 A8 A9 A10 A11 A12
WE
C197-1
Selection Guide
Maximum Access Time (ns)
Maximum Operating Current (mA)
Maximum Standby Current (mA)
7C197-12
12
150
30
7C197-15
15
140
30
7C197-20
20
135
30
7C197-25
25
95
30
7C197-35
35
95
30
7C197-45
45
30
Cypress Semiconductor Corporation • 3901 North First Street • San Jose • CA 95134 • 408-943-2600
Document #: 38-05049 Rev. **
Revised August 24, 2001
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