AMD Am27C256 Service Manual

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FINAL

Am27C256

256 Kilobit (32 K x 8-Bit) CMOS EPROM

DISTINCTIVE CHARACTERISTICS

■ Fast access time

— Speed options as fast as 45 ns

■ Low power consumption

— 20 µA typical CMOS standby current

■ JEDEC-approved pinout

■ Single +5 V power supply

■ ±10% power supply tolerance standard

■ 100% Flashrite™ programming

— Typical programming time of 4 seconds

■ Latch-up protected to 100 mA from –1 V to

+ 1 V

V

CC

■ High noise immunity

■ Versatile features for simple interfacing

— Both CMOS and TTL input/output compatibility — Two line control functions

■ Standard 28-pin DIP, PDIP, and 32-pin PLCC

packages

GENERAL DESCRIPTION

The Am27C256 is a 256-Kbit, ultraviolet erasable programmable read-only memory. It is organized as 32K words by 8 bits per word, operates from a single +5 V supply, has a static standby mode, and features fast single address location programming. Products are available in windowed ceramic DIP packages, as well as plastic one time programmable (OTP) PDIP and PLCC packages.

Data can be typically accessed in less than 55 ns, allowing high-p erformance m icroproces sors to ope rate without any WAIT states. The device offers separate Output Enable (OE#) and Chip Enable (CE#) controls,

BLOCK DIAGRAM

V

CC

V

SS

V

PP

OE# CE#

Output Enable

Chip Enable

and

Prog Logic

thus eliminating bus contention in a mul tiple bus microprocessor system.

AMD’s CMOS process technology provides high speed, low power, and high noise immunity. Typical power consumption is only 80 mW in active mode, and 100 µW in standby mode.

All signals are TTL levels, including programming signals. Bit locations may be programmed singly, in blocks, or at random. The device supports AMD’s Flashrite programming alg orithm (100 µs pulses), resulting in a typical programming time of 4 seconds.

Data Outputs

DQ0–DQ7

Output Buffers

A0–A14 Address

Inputs

Y

Decoder

X

Decoder

Y

Gating

262,144

Bit Cell

Matrix

Publication# 08007 Rev: I Amendment/0 Issue Date: May 1998

08007I-1

PRODUCT SELECTOR GUIDE

Family Part Number Am27C256

= 5.0 V ± 5% -255

V

Speed Options

Max Access Time (ns) 45 55 70 90 120 150 200 250 CE# (E#) Access (ns) 45 55 70 90 120 150 200 250 OE# (G#) Access (ns) 30 35 40 40 50 50 50 50

CC

= 5.0 V ± 10% -45 -55 -70 -90 -120 -150 -200

V

CC

CONNECTION DIAGRAMS Top View

DIP PLCC

PP

CC

V

PP

A12

A7 A6 A5 A4 A3 A2 A1 A0

DQ0 DQ1

DQ2

V

SS

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

Notes:

1. JEDEC nomenclature is in parenthesis.

2. Don’t use (DU) for PLCC.

V

CC

A14 A13 A8 A9 A11 OE# (G#) A10 CE# (E#) DQ7 DQ6

DQ5 DQ4 DQ3

08007I-2

A6 A5 A4

A3 A2 A1 A0

NC

DQ0

5 6

7

8 9 10

11 12 13

14

A7

15

DQ1

A12

DQ2

V

13130234

17

SS

DU

V

DU

18

32

DQ3

A14

A13

V

A8

29

A9

28

A11

27

NC

26

OE# (G#)

25

A10

24

CE# (E#)

23

DQ7

22

DQ6

21

19 2016

DQ5

DQ4

08007I-3

PIN DESIGNATIONS

LOGIC SYMBOL

A0–A14 = Address Inpu ts CE# (E#) = Chip Enable Input DQ0–DQ7 = Data Input/Outputs OE# (G#) = Output Enable Input V

CC

V

PP

V

SS

=VCC Supply Voltage = Program Voltage Input = Ground

NC = No Internal Connection

2 Am27C256

15

A0–A14

CE# (E#)

OE# (G#)

8

DQ0–DQ7

08007I-4

ORDERING INFORMATION UV EPROM Products

AMD standard products are available in several packages and operating ranges. The order number (Valid Combination) is formed by a combination of the following:

AM27C256 -45 D C

DEVICE NUMBER/DESCRIPTION

Am27C256 256 Kilobit (32 K x 8-Bit) CMOS UV EPROM

B

OPTIONAL PROCESSING

Blank = Standard Processing B = Burn-In

TEMPERATURE RANGE

C = Commercial (0°C to +70 I=Industrial (–40

E = Extended (–55°C to +125°C)

PACKAGE TYPE

D = 28-Pin Ceramic DIP (CDV028)

SPEED OPTION

See Product Selector Guide and Valid Combinations

°C to +85°C)

°C)

AM27C256-45 AM27C256-55 AM27C256-70

AM27C256-90 AM27C256-120 AM27C256-150 AM27C256-200 AM27C256-255

= 5.0 V ± 5%

V

CC

Valid Combinations

DC, DCB, DI, DIB

DC, DCB, DI, DIB, DE, DEB

DC, DCB, DI, DIB

Valid Combinations

Valid Combinations list configurations planned to be supported in volume for this device. Consult the local AMD sales office to confirm availability of specific valid combinations and to check on newly released combinations.

Am27C256 3

ORDERING INFORMATION OTP EPROM Products

AMD standard products are available in several packages and operating ranges. The order number (Valid Combination) is formed by a combination of the following:

AM27C256 -55 P C

OPTIONAL PROCESSING

Blank = Standard Processing

TEMPERATURE RANGE

C = Commercial (0 I=Industrial (–40

PACKAGE TYPE

P = 28-Pin Plastic DIP (PD 028) J = 32-Pin Square Plastic Leaded Chip Carrier (PL 032)

SPEED OPTION

See Product Selector Guide and Valid Combinations

°C to +70°C)

°C to +85°C)

DEVICE NUMBER/DES CR IP TIO N

Am27C256 256 Kilobit (32 K x 8-Bit) CMOS OTP EPROM

Valid Combinations

AM27C256-55 JC, PC

AM27C256-70

AM27C256-90 AM27C256-120

JC, PC, JI, PI

AM27C256-150 AM27C256-200 AM27C256-255

Valid Combinations

Valid Combinations list configurations planned to be supported in volume for this device. Consult the local AMD sales office to confirm availability of specific valid combinations and to check on newly released combinations.

4 Am27C256