UVEPROM

UVEPROM

UVEPROM

UVEPROM

UVEPROM

AS27C256

AS27C256

Rev. 2.0 7/06

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

2

Austin Semiconductor, Inc.

GENERAL DESCRIPTION

The AS27C256 series is a set of 262,144 bit, ultraviolet-light

erasable, electrically programmable read-only

memories.

These devices are fabricated using power-saving CMOS tech-

nology for high speed and simple interface with MOS and bipo-

lar circuits. All inputs (including program data inputs) can be

driven by Series 54 TTL circuits without the use of external

pullup resistors. Each output can drive one Series 54 TTL

circuit without external resistors. The data outputs are 3-state

for connecting multiple devices to a

common bus. The

AS27C256 is pin-compatible with 28-pin 256K ROMs and

EPROMs. It is offered in a 600mil dual-in-line ceramic package

(J suffix) and a 450 x 550 mil ceramic LCC (ECA suffix) rated for

operation from -55°C to 125°C.

Because this EPROM operates from a single 5V supply (in

the read mode), it is ideal for use in microprocessor-based sys-

tems. One other supply (12.75V) is needed for programming.

All programming signals are TTL level. This device is

pro-

grammable by the AMD FLASHRITE Pulse programming algo-

rithm. The FLASHRITE Pulse programming algorithm uses a

V

PP

of 12.75VV and a V

CC

of 6.25V for a nominal programming

time of four seconds. For programming outside the system,

existing EPROM programmers can be used. Locations can be

programmed singly, in blocks, or at random.

FUNCTIONAL BLOCK DIAGRAM*

* This symbol is in accordance with ANSI/IEEE std 91-1984 and IEC Publication 617-12.

A0

A1

A2

A3

A4

A5

DQ0

A6

DQ1

A7

DQ2

A8

DQ3

A9

DQ4

A10

DQ5

A11

DQ6

A12

DQ7

A13

A14

E\

G\

&

10

[PWR DWN]

9

8

7

6

5

4

3

25

24

21

23

2

26

27

20

22

EN

A

A

A

A

A

A

A

A

11

12

13

15

16

17

18

19

EPROM 32,768 x 8

0

14

A

0

32,767