Accutek
Microcircuit
Corporation
DESCRIPTION
The Accutek AK632256W-72 SRAM Module consists of fast high
performance SRAMs mounted on a low profile, 72 pin SIM Board.
The module utilizes four 28 pin 256K x 4 SRAMs in 400 mil SOJ
packages and four decoupling capacitors mounted on each side of
a printed circuit board.
The SRAMs used have common I/O functions and single output en-
able functions. Also, four separate chip select (CE) connections are
used to independently enable the four bytes. The modules can be
supplied in a variety of access time values from 12 nSEC to
45 nSEC in CMOS or BiCMOS technology.
The Accutek module is designed to have a maximum seated height
of 0.680 inch to provide for the lowest height off the board. By off-
set-mounting the back surface SRAMs the module can be mounted
in either angled or straight-up SIM sockets. The module conforms
to JEDEC standard sizes and pin-out configurations. Using four
pins for module memory density identification, PD
0
to PD
3
, mini-
mizes interchangeability and design considerations when changing
from one module size to another in customer applications.
AK632256W-72
262,144 x 32 Bit CMOS/BiCMOS
72 Pin Format
Static Random Access Memory
Front View
72-Pin SIM
FEATURES
·
262,144 x 32 bit organization
·
JEDEC Standardized 72 pin SIM or ZIP pinout
·
Common I/O, single OE functions with four separate chip se-
lects (CE)
·
Low height, 0.680 inch maximum
·
Upward compatible with 512K x 32 (AK632512) and 1 Meg x 32
(AK6321024)
·
Downward compatible with 32K x 32 (AK63232), 64K x 32
(AK63264) and 128K x 32 AK632128
·
Presence Detect PD
0
to PD
3
for identifying module density
·
Fast access times range from 12 nSEC BiCMOS to 45 nSEC
CMOS
·
TTL-compatible inputs and outputs
·
Single 5 volt power supply - AK632256W-72
·
Single 3.3 volt power supply - AK632256W-72/3.3
·
Operating temperature range in free air, 0
0
C to 70
0
C
ELECTRICAL SPECIFICATIONS
Timing diagrams and basic electrical characteristics are those of
the standard 256K x 4 SRAMs used to construct these modules.
Accutek’s module design allows the flexibility of selecting indus-
try-compatible 256K x 4 SRAMs from several semiconductor manu-
facturers.
PIN NOMENCLATURE
A
0
- A
17
CE
1
- CE
4
DQ
1
- DQ
32
OE
PD
0
- PD
3
Vcc
Vss
WE
NC
Address Inputs
Chip Enable
Data In/Data Out
Output Enable
Presence Detect
5v Supply
Ground
Write Enable
No Connect
PIN ASSIGNMENT
PIN #
SYMBOL
PIN #
SYMBOL
PIN #
SYMBOL
PIN #
SYMBOL
FUNCTIONAL DIAGRAM
CE4
CE3
A17
A16
OE
Vss
DQ25
DQ17
DQ26
DQ18
DQ27
DQ19
DQ28
DQ20
A3
A10
A4
A11
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
A5
A12
Vcc
A13
A6
DQ21
DQ29
DQ22
DQ38
DQ23
DQ31
DQ24
DQ32
Vss
A18/NC
A19/NC
NC
NC
1
2
3
4
5
6
7
8
9
10
11
12
13
NC
NC
PD2/NC
PD3/NC
Vss
PD0
PD1
DQ1
DQ9
DQ2
DQ10
DQ3
DQ11
DQ4
DQ12
Vcc
A0
A7
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
A1
A8
A2
A9
DQ13
DQ5
DQ14
DQ6
DQ15
DQ7
DQ16
DQ8
Vss
WE
A15
A14
CE2
CE1
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
MODULE OPTIONS
Leadless SIM: AK632256W-72
14
15
16
17
18
PD0 = Vss
PD1 = Vss
PD2 = Open
PD3 = Open
ACCUTEK [ ACCUTEK MICROCIRCUIT CORPORATION ]
