Am27C256-120DCB - Advanced Micro Devices

FINAL

Publicati on# 08007 Rev: IAmendment/0

Issue Date: May 1998

Am27C256

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

DISTINCTIVE CHARACTERISTICS

■Fast access time

— Speed options as fast as 45 ns

■Low power consumptio n

— 20 µA typical CMOS standby current

■JEDEC-approved pinout

■Single +5 V power supply

■±10% power supply tolerance standard

■100% Flashrite™ programm ing

— Typical programming time of 4 seconds

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

VCC + 1 V

■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 pro-

grammable 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, al-

lowing high-performance microprocessors to operate

without any WAIT states. The device offers separate

Output Enable (OE#) and Chip Enable (CE#) controls,

thus eliminating b us contention in a multiple b us micro-

proc esso r sys te m.

AMD’s CMOS process technology provides high

speed, low power, and high noise immunity. Typical

power consumption is only 80 mW in acti ve mode, and

100 µW in standby mode.

All signals are TTL levels, including programming sig-

nals. Bit locations may be programmed singly, in

blocks, or at random. The device supports AMD’s

Flashrite programming algorithm (100 µs pulses), re-

sulting in a typical programming time of 4 seconds.

BLOCK DIAGRAM

08007I-1

A0–A14

Address

Inputs

CE#

OE#

VCC

VSS

VPP

Data Outputs

DQ0–DQ7

Output

Buffers

Gating

262,144

Bit Cell

Matrix

Decoder

Output Enable

Chip Enable

and

Prog Logic

2 Am27C256

PRODUCT SELECTOR GUIDE

CONNECTION DIAGRAMS

Top View

DIP PLCC

Notes:

1. JEDEC nomenclature is in parenthesis.

2. Don’t use (DU) for PLCC.

PIN DESIGNATIONS

A0–A14 = Address Inputs

CE# (E#) = Chip Enable Input

DQ0–DQ7 = Data Input/Outputs

OE# (G#) = Output Enable Input

VCC =V

CC Supply Voltage

VPP = Program Voltage Input

VSS = Ground

NC = No Internal Connection

LOGIC SYMBOL

Family Part Number Am27C256

Speed Options VCC = 5.0 V ± 5% -255

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

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

DQ0

DQ1

DQ2

VSS

A11

OE# (G#)

A10

CE# (E#)

DQ7

VCC

A14

DQ6

A13

DQ5

DQ4

DQ3

VPP

A12

08007I-2

DQ5

DQ4

DQ3

13130234

13 17 18 19 2016

DQ0

A11

OE# (G#)

A10

CE# (E#)

DQ7

DQ6

A12

VPP

VCC

A14

A13

DQ1

DQ2

VSS

08007I-3

DQ0–DQ7

A0–A14

CE# (E#)

OE# (G#)

08007I-4

Am27C256 3

ORDERING INFORMATION

UV EPROM Products

AMD standard products are a vailable in se veral packages and operating ranges. The order number (V alid Combination) is formed

by a combination of the following:

Valid Combinations

Valid Combinations list configurations planned to be sup-

ported in v olume for this device. Consult the local AMD sales

office to confirm av ailability of specific valid combinations and

to check on newly released combinations.

DEVICE NUMBER/DESCRIPTION

Am27C256

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

AM27C256 -45 D C

OPTIONAL PROCESSING

Blank = Standard Pro ces sin g

B = Burn-In

TEMPERATURE RANGE

C = Commercial (0°C to +70°C)

I=Industrial (–40°C to +85°C)

E = Extended (–55°C to +125°C)

PACKAGE TYPE

D = 28-Pin Ceramic DIP (CDV028)

SPEED OPTION

See Product Selector Guide and Valid Combinations

Valid Combinations

AM27C256-45 DC, DCB, DI, DIB

AM27C256-55

AM27C256-70

DC, DCB, DI, DIB, DE, DEB

AM27C256-90

AM27C256-120

AM27C256-150

AM27C256-200

AM27C256-255

VCC = 5.0 V ± 5% DC, DCB, DI, DIB

4 Am27C256

ORDERING INFORMATION

OTP EPROM Products

AMD standard products are a vailable in se veral packages and operating ranges. The order number (V alid Combination) is formed

by a combination of the following:

Valid Combinations

Valid Combinations list configurations planned to be sup-

ported in v olume for this device. Consult the local AMD sales

office to confirm av ailability of specific valid combinations and

to check on newly released combinations.

DEVICE NUM BE R/ DES CR IP TIO N

Am27C256

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

AM27C256 -55 P C

OPTIONAL PROCESSING

Blank = Standard Processing

TEMPERATURE RANGE

C = Commercial (0°C to +70°C)

I=Industrial (–4 0°C to +85°C)

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

Valid Combinations

AM27C256-55 JC, PC

AM27C256-70

JC, PC, JI, PI

AM27C256-90

AM27C256-120

AM27C256-150

AM27C256-200

AM27C256-255

Am27C256 5

FUNCTIONAL DESCRIPTION

Device Erasure

In order to clear all locations of their programmed con-

tents , the de vice must be e xposed to an ultra violet light

source. A dosage of 15 W seconds/cm2 is required to

completely erase the device. This dosage can be ob-

tained by exposure to an ultraviolet lamp—wavelength

of 2537 Å—with intensity of 12,000 µW/cm2 for 15 to 20

minutes. The device should be directly under and about

one inch from the source, and all filters should be re-

moved from the UV light source prior to erasure.

Note that all UV erasable devices will erase with light

sources hav ing wav elengths shorter than 4000 Å, such

as fluorescent light and sunlight. Although the erasure

process happens over a much longer time period, ex-

posure to any light source should be prevented for

maximum system reliability. Simply cover the package

window with an opaque label or substance.

Device Programming

Upon delivery, or after each erasure, the device has

all of it s bits in the “ONE”, or HIGH stat e. “ZE ROs” are

loaded into the device through the programming pro-

cedure.

The device enters the programming mode when 12.75

V ± 0.2 5 V is applied to the VPP pin, OE# is at VIH and

CE# is at VIL.

For programming, the data to be programmed is ap-

plied 8 bits in parallel to the data pins.

The flowchart in the Programming section of the

EPROM Products Data Book (Section 5, Figure 5-1)

shows AMD’s Flashrite algorithm. The Flashrite algo-

rithm reduces programming time by using a 100 µs pro-

gramming pulse and by giving each address only as

many pulses to reliably program the data. After each

pulse is applied to a gi ven address, the data in that ad-

dress is verified. If the data does not verify, additional

pulses are given until it verifies or the maximum pulses

allowed is reached. This process is repeated w hile se-

quencing through eac h address of the device. This part

of the algorithm is done at VCC = 6.25 V to assure that

each EPROM bit is programmed to a sufficiently high

threshold voltage. After the final address is completed,

the entire EPROM memory is verified at VCC = VPP =

5.25 V.

Please ref er to Section 5 of the EPR OM Products Data

Book f or additional prog ramming information and spec-

ifications.

Program Inhibit

Programming different data to multiple devices in par-

allel is easily accomplished. Except for CE#, all like in-

puts of the devices may be common. A TTL low-level

program pulse applied to one device’s CE# input with

VPP = 12.75 V ± 0.25 V and OE# HIGH will program

that particular device. A high-level CE# input inhibits

the other devices from being programmed.

Program Verify

A v erificat ion should be performed on the prog r ammed

bits to determine that the y were correct ly programmed.

The verify should be perf ormed with OE# at VIL, CE# at

VIH, and VPP between 12.5 V and 13.0 V.

Autoselect Mode

The autoselect mode provides manufacturer and de-

vice identification through identifier codes on DQ0–

DQ7. This mode is primarily intended for programming

equipment to automatically match a device to be pro-

grammed with its corresponding programming algo-

rithm. This mode is functional in the 25°C ± 5°C

ambient temperature range that is required when pro-

gra mming the device.

To activate this mode, the programming equipment

must force VH on address line A9. Two identifier bytes

may then be sequenced from the de vice outputs by tog-

gling address line A0 from VIL to VIH (that is, changing

the address from 00h to 01h). All other address lines

must be held at VIL during the autoselect mode.

Byte 0 (A0 = VIL) represents the manufacturer code,

and Byte 1 (A0 = VIH), the device identifier code. Both

codes have odd parity, with DQ7 as the parity bit.

Read Mode

To obtain data at the device outputs , Chip Enable (CE#)

and Output Enab le (OE#) must be driv en low . CE# con-

trols the po wer to the de vice and is typically used t o se-

lect the device. OE# ena b les the de v ice t o out put data,

independent of device selection. Addresses must be

stable for at least tACC–tOE. Refer to the Switching

Waveforms section for the timing diag ram.

Standby Mode

The de vice enters the CMOS standby mode when CE#

is at VCC ± 0.3 V. Maximum VCC current is reduced to

100 µA. The device enters the TTL-standby mode

when CE# is at VIH. Maximum VCC current is reduced

to 1.0 mA. When in either standby mode, the device

places its outputs in a high-impedance state, indepen-

dent of the OE# input.

Output OR-Tieing

To accommodate multiple memory connections, a

two-line control function provides:

■Low memory power dissipation, and

■Assur ance that outpu t bus contention will not oc cur.

CE# should be decoded and used as the primary de-

vice-selecting funct ion, whi le OE# be made a common

6 Am27C256

connection to all devices in the array and connected to

the READ line from the system control bus. This as-

sures that all deselected memor y devices are in their

low-power standby mode and that the output pins are

only activ e when data is desired fr om a particular mem-

ory device.

System Applications

During the switch between active and standby condi-

tions, transient current peaks are produced on the ris-

ing and f alling edges of Chip Enab le . The magnitude of

these transient current peaks is dependent on the out-

put capacitance loading of t he device. At a minim um, a

0.1 µF ceramic capacitor (high frequency, low inherent

inductance) should be used on each device between

VCC and VSS to minim ize transient effects. In addition,

to overcome the voltage drop caused by the inductive

effects of the printed circuit board traces on EPR OM ar-

rays, a 4.7 µF bulk electrolytic capacitor should be used

between V CC and VSS for each eight de vices. The loca-

tion of the capacitor should be close to where the

power supply is connected to the array.

MODE SELECT TABLE

Notes:

1. VH = 12.0 V

0.5 V.

2. X = Either VIH or VIL.

3. A1–A8 and A10–14 = VIL

4. See DC Programming Characteristics for VPP voltage during programmin g.

Mode CE# OE# A0 A9 VPP Outputs

Read VIL VIL XX XD

OUT

Output Disable X VIH X X X High Z

Standby (TTL) VIH X X X X High Z

Standby (CMOS) VCC ± 0.3 V X X X X High Z

Program VIL XX XV

PP DIN

Program Verify VIL VIL XXV

PP DOUT

Program Inhibit VIH VIH XXV

PP High Z

Autoselect

(Note 3) Manufacturer Cod e VIL VIL VIL VHX 01h

Device Code VIL VIL VIH VHX 10h

Am27C256 7

ABSOLUTE MAXIMUM RATINGS

Storage Temperature

OTP Products . . . . . . . . . . . . . . . . . . –65°C to +125°C

All Other Products . . . . . . . . . . . . . . –65°C to +150°C

Ambient Temperat ure

with Power Applied. . . . . . . . . . . . . . –55°C to +125°C

Voltage with Respect to VSS

All pins except A9, VPP

, VCC . . –0.6 V to VCC + 0.6 V

A9 and VPP (Note 2) . . . . . . . . . . . . .–0.6 V to 13.5 V

VCC (Note 1). . . . . . . . . . . . . . . . . . . . .–0.6 V to 7.0 V

Notes:

1. Minimum DC vo ltage on inpu t or I/O pins – 0.5 V. Dur ing

voltage transitions, the input may ov ershoot VSS to –2.0 V

for periods of u p to 20 ns. Max imum DC voltage o n inp ut

and I/O pins is V

+ 5 V. During voltage transitions, input

and I/O pins may ov ershoot to V

+ 2.0 V for periods up

to 20 ns.

2. Minimum DC input voltage on A9 is –0.5 V. During voltage

transitions, A9 and VPP may overshoot V SS

to –2.0 V for

periods of up to 20 ns. A9 and VPP must not exceed +13.5

V at any time.

Stresse s above thos e listed unde r “Absolute Ma ximum Rat-

ings” may caus e per ma nent d amage to the device. This is a

stress ratin g on ly; fun ctio nal ope ration of t he d evice at the se

or any other conditions above those indicated in the opera-

tional sections of this specification is not implied. Exposure of

the device to absolute maximum ratings for extended periods

may affect device reliability.

OPERATING RANGES

Commercial (C) Devices

Ambient Temperature (TA) . . . . . . . . . . . 0°C to +70°C

Industrial (I) De vices

Ambient Temperature (TA) . . . . . . . . .–40°C to +85°C

Extended (E) Devices

Ambient Temperature (TA) . . . . . . . .–55°C to +125°C

Supply Read Vol tages

VCC for ± 5% devices . . . . . . . . . . +4.75 V to +5.25 V

VCC for ± 10% devices . . . . . . . . . +4.50 V to +5.50 V

Operating ranges define those limits between which the func-

tionality of the device is guaranteed.

8 Am27C256

DC CHARACTERISTICS over operating range (unless otherwise specified)

Caution: The device must not be removed from (or inserted into) a socket when VCC or VPP is applied.

Notes:

1. VCC must be applied simultaneously or before VPP

, and removed simultaneously or after VPP

2. ICC1 is tested with OE# = VIH to simulate open outputs.

3. Minimum DC Input Voltage is –0.5 V. During transitions, the inputs may overshoot to –2.0 V for periods less than 20 ns.

Maximum DC Voltage on output pins is VCC + 0.5 V, which may overshoot to VCC + 2.0 V for periods less than 20 ns.

Figure 1. Typical Supply Current vs. Frequency

VCC = 5.5 V, T = 25°CFigure 2. Typical Supply Current vs. Temperature

VCC = 5.5 V, f = 10 MHz

Parameter

Symbol Parameter Description Test Conditions Min Max Unit

VOH Output HIGH Voltage IOH = –400 µA 2.4 V

VOL Output LOW Voltage IOL = 2.1 mA 0.45 V

VIH Input HIGH Voltage 2.0 VCC + 0.5 V

VIL Input LOW Voltage –0.5 +0.8 V

ILI Input Load Current VIN = 0 V to VCC 1.0 µA

ILO Output Leakage Current VOUT = 0 V to VCC C/I Devices 1.0 µA

E Devices 5.0

ICC1 VCC Active Current (Note 2) CE# = VIL, f = 10 MHz,

IOUT = 0 mA 25 mA

ICC2 VCC TTL Standby Current CE# = VIH 1.0 mA

ICC3 VCC CMOS Standby Current CE# = VCC ± 0.3 V 100 µA

IPP1 VPP Supply Current (Read) CE# = OE# = VIL, VPP = VCC 100 µA

08007I-5

12345678910

Frequency in MHz

Supply Current

in mA

08007I-6

–75 –50 –55 0 25 50 75 100 125 150

Tem peratu re in °C

Supply Current

in mA

Am27C256 9

TEST CONDITIONS

Table 1. Test Specifications

SWITCHING TEST WAVEFORM

KEY TO SWITCHING WAVEFORMS

2.7 kΩ

CL6.2 kΩ

5.0 V

Device

Under

Test

08007I-7

Figure 3. Test Setup

Note:

Diodes are IN3064 or equivalents.

Test Condition -45, -55

and -70 All

others Unit

Output Load 1 TTL gate

Output Load Capacitance, CL

(including jig cap aci tan ce) 30 100 pF

Input Rise and Fall Times ≤ 20 ns

Input Pulse Levels 0.0–3.0 0.45–2.4 V

Input timing measurement

reference levels 1.5 0.8, 2.0 V

Output timing measurement

reference levels 1.5 0.8, 2.0 V

2.4 V

0.45 V Input Output

Test Points

2.0 V 2.0 V

0.8 V

08007I-8

3 V

0 V Input Output

1.5 V 1.5 V

Test Points

Note: For CL = 100 pF.Note: For CL = 30 pF.

KS000010-PAL

WAVEFORM INPUTS OUTPUTS

Steady

Changing from H to L

Changi ng from L to H

Don’t Care, Any Change Permitted Changing, State Unknown

Does Not Apply Center Line is High Impedance State (High Z)

10 Am27C256

AC CHARACTERISTICS

Caution: Do not remove the device from (or insert it into) a socket or board that has VPP or VCC applied.

Notes:

1. VCC must be applied simultaneously or before VPP

, and removed simultaneously or after VPP

2. This parameter is sampled and not 100% tested.

3. Switching characteristics are over operating range, unless otherwise specified.

4. See Figure 3 and Table 1 for test specifications.

SWITCHING WAVEFORMS

Notes:

1. OE# may be delayed up to tACC – tOE after the falling edge of the addresses without impact on tACC.

2. tDF is specified from OE# or ‘CE#, whichever occurs first.

PACKAGE CAPACITANCE

Notes:

1. This parameter is only sampled and not 100% tested.

2. TA = +25

C, f = 1 MHz.

Parameter Symbols

Description Test Setup

Am27C256

UnitJEDEC Standard -45 -55 -70 -90 -120 -150 -200 -255

tAVQV tACC Address to Output Delay CE#,

OE# = VIL Max 45 55 70 90 120 150 200 250 ns

tELQV tCE Chip Enable to Output Delay OE# = VIL Max 45 55 70 90 120 150 200 250 ns

tGLQV tOE Output Enable to Output

Delay CE# = VIL Max3035404050505050ns

EHQZ

tGHQZ

tDF

(Note 2)

Chip Enable High or Output

Enable High to Output High Z,

Whichever Occurs First Max2525252530303030ns

AXQX tOH

Output Hold Time from

Addresses, CE# or OE#,

Whichever Occurs First Min00000000ns

Addresses

CE#

OE#

Output

08007I-9

Addresses Valid

High Z High Z

tCE

Valid Output

2.4

0.45

2.0

0.8 2.0

0.8

tACC

(Note 1)

tOE tDF (Note 2)

tOH

Parameter Symbol Parameter

Description Test Conditions

CDV028 PL 032 PD 028

UnitTyp Max Typ Max Typ Max

CIN Input Capacitance VIN = 0 8 12 8 12 6 10 pF

COUT Output Capacitance VOUT = 0 812812810pF

Am27C256 11

PH YS ICAL DIMENSIONS *

CDV028—28-Pin Ceramic Dual In-Line Package, UV Lens (measured in inches)

* For reference only. BSC is an ANSI standard for Basic Space Centering.

PD 028—28-Pin Plastic Dual In-Line Package (measured in inches)

TOP VIEW

SIDE VIEW END VIEW

INDEX AND

TERMINAL NO. 1

I.D. AREA

.565

.605

1.435

1.490

.005 MIN .045

.065 .014

.026 .100 BSC

.015

.060

.160

.220

.125

.200

BASE PLANE

SEATING PLANE

.300 BSC .600

BSC .008

.018

94°

105°

.700

MAX

16-000038H-3

CDV028

DF10

3-30-95 ae

DATUM D

CENTER PLANE

DATUM D

CENTER PLANE

UV Lens

Pin 1 I.D.

1.440

1.480

.530

.580

.005 MIN

.045

.065

.090

.110

.140

.225

.120

.160 .014

.022

SEATING PLANE

.015

.060

.630

.700

0°

10°

.600

.625

16-038-SB-AG

PD 028

DG75

7-13-95 ae

28 15

.008

.015

12 Am27C256

PH YS ICAL DIMENSIONS

PL 032—32-Pin Plastic Leaded Chip Carrier (measured in inches)

REVISION SUMMARY FOR AM27C256

Revision I

Global

Changed for m atting to match current data sheets.

Distinctive Characteristics

Fast access time:

Changed “Speed options as fast as

55 ns” to “Speed options as f ast as 45 ns”.

Product Selector Guide

Added the -45 speed option.

Ordering In formation

UV EPROM Products:

Added the AM27C256-45 Valid

Combination.

Test Conditions

Table 1. Test Specifications:

Added the -45 speed op-

tion.

AC Characteristi cs

Added the -45 speed option.

Trademarks

AMD, the AMD logo, and combinations thereof are trademarks of Advanced Micro Devices, Inc.

Flashrite is a trademark of Advanced Micro Devices, Inc.

Product names used in this publication are for identification purposes only and may be trademarks of their respective companies.

.050 REF.

.026

.032 TOP VIEW

Pin 1 I.D.

.485

.495

.447

.453

.585

.595

.547

.553

16-038FPO-5

PL 032

DA79

6-28-94 ae

SIDE VIEW

SEATING

PLANE

.125

.140

.009

.015

.080

.095

.042

.056

.013

.021

.400

REF. .490

.530