Datasheet Am27C256

FINAL

Am27C256
256 Kilobit (32 K x 8-Bit) CMOS EPROM
DISTINCTIVE CHARACTERISTICS
s Fast access time — Speed options as fast as 45 ns s Low power consumption — 20 µA typical CMOS standby current s JEDEC-approved pinout s Single +5 V power supply s ±10% power supply tolerance standard s 100% Flashrite™ programming — Typical programming time of 4 seconds s Latch-up protected to 100 mA from –1V to VCC + 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, 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-performance microprocessors to operate without any WAIT states. The device offers separate Output Enable (OE#) and ChipEnable (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 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 devicesupports AMD’s Flashrite programming algorithm (100 µs pulses), resulting in a typical programming time of 4 seconds.

BLOCK DIAGRAM
VCC VSS VPP OE# CE# Output Enable Chip Enable and Prog Logic Y Decoder A0–A14 Address Inputs Output Buffers Data Outputs DQ0–DQ7

Y Gating

X Decoder

262,144 Bit Cell Matrix
08007I-1
Publication# 08007 Rev: I Issue Date: May 1998 Amendment/0

PRODUCTSELECTOR GUIDE
Family Part Number Speed Options VCC = 5.0 V ± 5% VCC = 5.0 V ± 10% -45 45 45 30 -55 55 55 35 -70 70 70 40 -90 90 90 40 -120 120 120 50 -150 150 150 50 -200 200 200 50 250 250 50 Am27C256 -255

Max Access Time (ns) CE# (E#) Access (ns) OE# (G#) Access (ns)

CONNECTION DIAGRAMS Top View
DIP
A7 A12

PLCC
VCC A14 A13 VPP DU

VPP A12 A7 A6 A5 A4 A3 A2 A1 A0 DQ0 DQ1 DQ2 VSS

12 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

VCC A14 A13 A8 A9 A11 OE# (G#) A10 CE# (E#) DQ7 DQ6 DQ5 DQ4 DQ3
08007I-2

4 3 2 1 32 31 30 A6 A5 A4 A3 A2 A1 A0 NC DQ0 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 VSS DU DQ3 DQ4 DQ1 DQ2 DQ5 29 28 27 26 25 24 23 22 21 A8 A9 A11 NC OE# (G#) A10 CE# (E#) DQ7 DQ6

08007I-3

Notes: 1. JEDEC nomenclature is inparenthesis. 2. Don’t use (DU) for PLCC.

PIN DESIGNATIONS
A0–A14 CE# (E#) DQ0–DQ7 OE# (G#) VCC VPP VSS NC = Address Inputs = Chip Enable Input = Data Input/Outputs = Output Enable Input = VCC Supply Voltage = Program Voltage Input = Ground = No Internal Connection

LOGIC SYMBOL

15 A0–A14 DQ0–DQ7 CE# (E#) 8

OE# (G#)
08007I-4

2

Am27C256

ORDERING INFORMATION UV EPROM Products
AMDstandard 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

B

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 (–55°C to +125°C) PACKAGE TYPE D = 28-Pin Ceramic DIP(CDV028) SPEED OPTION See Product Selector Guide and Valid Combinations

DEVICE NUMBER/DESCRIPTION Am27C256 256 Kilobit (32 K x 8-Bit) CMOS UV EPROM

Valid Combinations AM27C256-45 DC, DCB, DI, DIB AM27C256-55 AM27C256-70 AM27C256-90 AM27C256-120 AM27C256-150 AM27C256-200 AM27C256-255 VCC = 5.0 V ± 5% DC, DCB, DI, DIB DC, DCB, DI, DIB, DE, DEB

Valid Combinations Valid Combinations list...