1

512K (64K x 8)

Multiplexed

Addresses/

Outputs

OTP EPROM

AT27C520

Features

– 20 mA max. Active at 5 MHz

± 10% Supply

– 2,000V ESD Protection

– 200 mA Latchup Immunity

µµµµs/byte (typical)

Description

The AT27C520 is a low-power, high performance 524,288 bit one-time programmable

read only memory (OTP EPROM) organized 64K by 8 bits. It incorporates latches for

the 8 lower order address bits to multiplex with the 8 data bits. This minimizes system

chip count, reduces cost, and simplifies the design of multiplexed bus systems. It

requires only one 5V power supply in normal read mode operation. Any byte can be

accessed in less than 70 ns, eliminating the need for speed reducing WAIT states on

high performance microprocessor systems.

Atmel’s scaled CMOS technology provides high speed, lower active power consump-

tion, and significantly faster programming. Power consumption is typically only 8 mA

in Active Mode.

The AT27C520 is available in 173 mil, 20-pin TSSOP; 300 mil, 20-pin SOIC; and 28-

pin TSOP, one-time programmable (OTP) plastic packages.

Rev. 0752C-C–01/98

Pin Configurations

Pin Name

Function

A8 - A15

Addresses

AD0 - AD7

Addresses/Outputs

OE /V

PP

Output Enable/V

PP

ALE

Address Latch Enable

SOIC Top View

1

2

3

4

5

6

7

8

9

10

20

19

18

17

16

15

14

13

12

11

OE/VPP

A15

A13

A11

A9

AD0

AD2

AD4

AD6

GND

VCC

ALE

A14

A12

A10

A8

AD1

AD3

AD5

AD7

(continued)

TSOP Top View

22

23

24

25

26

27

2

3

4

5

6

7

21

20

19

18

17

16

15

14

13

12

11

10

9

8

A10

NC

NC

A12

A14

ALE

VCC

OE/VPP

A15

A13

A11

NC

NC

A9

A8

NC

NC

AD1

AD3

AD5

AD7

GND

AD6

AD4

AD2

NC

NC

AD0

28

1

TSSOP Top View

1

2

3

4

5

6

7

8

9

10

20

19

18

17

16

15

14

13

12

11

A10

A12

A14

ALE

VCC

OE/VPP

A15

A13

A11

A9

A8

AD1

AD3

AD5

AD7

GND

AD6

AD4

AD2

AD0