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

A14

A13

A8

A9

A11

OE

A10

CE/PGM

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

NC

OE

CE/PGM

NC

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

TOP VIEW

Chip Carrier

CERDIP

PIN CONFIGURATION

4-17

MILITARY HIGH SPEED 32K x 8 CMOS EPROM

KEY FEATURES

— 55 ns

— Latch-up Immunity Up to 200 mA

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 µA 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

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

DIN

Program

Verify

XVIL

XX

DOUT

Program

Inhibit

VIH VIH

XX

VPP

VIL

VIL VH

2

VIL VCC VCC

23 H

4

VIL

VIL VH

2

VIH VCC VCC

EO H

5

MODE SELECTION

NOTES:

4. Manufacturer Signature.

5. Device Signature.

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