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PRODUCT SELECTION GUIDE
PARAMETER
WS57C256F-55
WS57C256F-70
Address Access Time (Max)
55 ns
70 ns
Output Enable Time (Max)
25 ns
30 ns
WS57C256F
VCC
A14
A13
A8
A9
A11
OE
A10
CE/PGM
O7
O6
O5
O4
O3
VPP
A12
A7
A6
A5
A4
A3
A2
A1
A0
O0
O1
O2
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
A8
A9
A11
NC
OE
A10
CE/PGM
O7
O6
A6
A5
A4
A3
A2
A1
A0
NC
O0
A
7
A
12
V
PP
NC
V
CC
A
14
A
13
O1 O2
NC O3 O4 O5
1
43
2
32 31 30
29
28
27
26
25
24
23
22
21
5
6
7
8
9
10
11
12
13
14 15 16 17 18 19 20
GND
TOP VIEW
Chip Carrier
CERDIP
PIN CONFIGURATION
4-17
MILITARY HIGH SPEED 32K x 8 CMOS EPROM
KEY FEATURES
Fast Access Time
EPI Processing
— 55 ns
— Latch-up Immunity Up to 200 mA
Low Power Consumption
Standard EPROM Pinout
DESC SMD No. 5962-86063
GENERAL DESCRIPTION
The WS57C256F is a High Performance 256K UV Erasable Electrically Programmable Read Only Memory. It is
manufactured using an advanced CMOS process technology enabling it to operate at speeds as fast as 55 ns
Access Time.
Two major features of the WS57C256F are its Low Power and High Speed. While operating in a TTL environment it
consumes less than 120 mA while cycling at full speed. Additionally, the WS57C256F can be placed in a standby
mode which drops operating current below 5 mA in a TTL environment and 500 A in a CMOS environment.
The WS57C256F also has exceptional output drive capability. It can source 4 mA and sink 16 mA per output.
The WS57C256F is configured in the standard EPROM pinout which provides an easy upgrade path for systems
which are currently using standard EPROMs.
PINS
CE/
OE
A9
A0 VPP VCC OUTPUTS
MODE
PGM
Read
VIL
XX
VCC VCC
DOUT
Output
Disable
XVIH
XX
VCC VCC
High Z
Standby
VIH
XX
X
VCC VCC
High Z
Program
VIL
VIH
XX
VPP
2 VCC
DIN
Program
Verify
XVIL
XX
VPP2 VCC
DOUT
Program
Inhibit
VIH VIH
XX
VPP
2 VCC High Z
Signature3
VIL
VIL VH
2
VIL VCC VCC
23 H
4
VIL
VIL VH
2
VIH VCC VCC
EO H
5
MODE SELECTION
NOTES:
1. X can be VIL or VIH.
4. Manufacturer Signature.
2. VIH = VPP = 12.75 ± 0.25 V.
5. Device Signature.
3. A1 – A8, A10 – A14 = VIL.
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