
256K x 8 Static RAM Module
Functional Description
CYM1441
Cypress Semiconductor Corporation
Document #: 38-05271 Rev. **
3901 North First Street
San Jose
CA 95134
408-943-2600
Revised March 15, 2002
41
Features
High-density 2-megabit SRAM module
High-speed CMOS SRAMs
—Access time of 20 ns
Low active power
—5.3W (max.)
SMD technology
Separate data I/O
60-pin ZIP package
TTL-compatible inputs and outputs
Low profile
—Max. height of 0.5 in.
Small PCB footprint
—1.14 sq. in.
The CYM1441 is a very high performance 2-megabit static
RAM module organized as 256K words by 8 bits. The module
is constructed using eight 256K x 1 static RAMs in SOJ pack-
ages mounted onto an epoxy laminate substrate with pins. Two
chip selects (CS
L
and CS
U
) are used to independently enable
the upper and lower 4 bits of the data word. Writing to the
memory module is accomplished when the chip select (CS)
and write enable (WE) inputs are both LOW. Data on the eight
input pins (DI
through DI
) is written into the memory location
specified on the address pins (A
0
through A
17
). Reading the
device is accomplished by taking chip select (CS) LOW while
write enable (WE) remains inactive or HIGH. Under these con-
ditions, the contents of the memory location specified on the
address pins will appear on the appropriate data output pins
(DO
through DO
). The data output pins remain in a high-
impedance state unless the module is selected and write en-
able (WE) is HIGH.Two pins (PD
0
and PD
1
) are used to identify
module memory density in applications where alternate ver-
sions of the JEDEC-standard modules can be interchanged.
Logic Block Diagram
Pin Configuration
ZIP
TopView
A
0
- A
17
WE
CS
U
CS
L
DI
4
- DI
7
DI
0
- DI
3
DO
4
- DO
7
DO
0
- DO
3
(OPEN)PD
0
NC
V
CC
DI
0
DO
0
A
0
A
2
A
4
A
6
GND
DI
1
DO
1
WE
A
9
CS
L
NC
NC
V
CC
DI
2
DO
2
A
10
A
12
A
14
A
16
NC
DI
3
DO
3
NC
NC
GND
GND
PD
1
(GND)
NC
DI
4
DO
4
NC
A
1
A
3
A
5
A
7
DI
5
DO
5
V
CC
A
8
NC
CS
U
NC
NC
DI
6
DO
6
GND
A
11
A
13
A
15
A
17
DI
7
DO
7
V
CC
NC
NC
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
60
1
3
5
7
9
11
13
15
17
19
21
23
25
27
29
31
33
35
37
39
41
43
45
47
49
51
53
55
57
59
256K x 1
SRAM
256K x 1
SRAM
256K x 1
SRAM
256K x 1
SRAM
256K x 1
SRAM
256K x 1
SRAM
256K x 1
SRAM
256K x 1
SRAM