Publication# 08007
Rev. H
Amendment /0
Issue Date: May 1995
2-32
Advanced
Micro
Devices
Am27C256
256 Kilobit (32,768 x 8-Bit) CMOS EPROM
FINAL
DISTINCTIVE CHARACTERISTICS
s
Fast access time
-- 55 ns
s
Low power consumption
-- 20
A typical CMOS standby current
s
JEDEC-approved pinout
s
Single +5 V power supply
s
10% power supply tolerance available
s
100% Flashrite programming
-- Typical programming time of 4 seconds
s
Latch-up protected to 100 mA from 1 V to
V
CC
+ 1 V
s
High noise immunity
s
Versatile features for simple interfacing
-- Both CMOS and TTL input/output
compatibility
-- Two line control functions
s
Standard 28-pin DIP, PDIP, 32-pin TSOP and
PLCC packages
GENERAL DESCRIPTION
The Am27C256 is a 256K-bit 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 sin-
gle address location programming. Products are avail-
able in windowed ceramic DIP packages as well as plas-
tic one time programmable (OTP) PDIP, TSOP, and
PLCC packages.
Typically, any byte can be accessed in less than 55 ns,
allowing operation with high-performance microproces-
sors without any WAIT states. The Am27C256 offers
separate Output Enable (
OE
) and Chip Enable (
CE
)
controls, thus eliminating bus contention in a multiple
bus microprocessor system.
AMD's CMOS process technology provides high speed,
low power, and high noise immunity. Typical power con-
sumption is only 80 mW in active mode, and 100
W in
standby mode.
All signals are TTL levels, including programming sig-
nals. Bit locations may be programmed singly, in blocks,
or at random. The Am27C256 supports AMD's Flashrite
programming algorithm (100
s pulses) resulting in typi-
cal programming time of 4 seconds.
BLOCK DIAGRAM
V
CC
V
SS
Output Enable
Chip Enable
and
Prog Logic
Y
Decoder
X
Decoder
CE
OE
Output
Buffers
Y
Gating
262,144
Bit Cell
Matrix
A0A14
Address
Inputs
Data Outputs
DQ0DQ7
08007H-1
V
PP
AMD
2-35
Am27C256
ORDERING INFORMATION
UV EPROM Products
DEVICE NUMBER
Am27C256
256 Kilobit (32,768 x 8-Bit) CMOS UV EPROM
PACKAGE TYPE
D = 28-Pin Ceramic DIP (CDV028)
Valid Combinations
AMD Standard products are available in several packages and operating ranges. The order number (Valid Combination) is
formed by a combination of:
B
C
D
-55
AM27C256
OPTIONAL PROCESSING
Blank = Standard Processing
B = Burn-in
TEMPERATURE RANGE
C = Commercial (0
C to +70
C)
I
= Industrial (40
C to +85
C)
E = Extended Commercial (55
C to +125
C)
SPEED OPTION
See Product Selector Guide and Valid Combinations
AM27C256-55
AM27C256-70
DC, DCB, DI, DIB
AM27C256-90
AM27C256-120
AM27C256-150
AM27C256-200
AM27C256-255
DC, DCB, DI,
DIB, DE, DEB
Valid Combinations
Valid Combinations list configurations planned to be
supported in volume for this device. Consult the lo-
cal AMD sales office to confirm availability of specific
valid combinations and to check on newly released
combinations.
DC, DCB, DI, DIB
AMD
2-36
Am27C256
ORDERING INFORMATION
OTP Products
DEVICE NUMBER
Am27C256
256 Kilobit (32,768 x 8-Bit) CMOS OTP EPROM
Valid Combinations
AM27C256-55
AM27C256-70
AM27C256-90
AM27C256-120
AM27C256-150
AM27C256-200
AM27C256-255
PACKAGE TYPE
P = 28-Pin Plastic DIP (PD 028)
J = 32-Pin Rectangular Plastic Leaded Chip
Carrier (PL 032)
E = 32-Pin TSOP (TS 032)
AMD Standard products are available in several packages and operating ranges. The order number (Valid Combination) is
formed by a combination of:
C
P
-55
AM27C256
OPTIONAL PROCESSING
Blank = Standard Processing
TEMPERATURE RANGE
C = Commercial (0
C to +70
C)
I
= Industrial (40
C to + 85
C)
SPEED OPTION
See Product Selector Guide and Valid Combinations
JC, PC, EC,
JI, PI, EI
Valid Combinations
Valid Combinations list configurations planned to be
supported in volume for this device. Consult the lo-
cal AMD sales office to confirm availability of specific
valid combinations and to check on newly released
combinations.
JC, PC, EC
PDF 
ZIP
