UVEPROM
SMJ27C256
AS27C256
Austin Semiconductor, Inc.
GENERAL DESCRIPTION
The SMJ27C256 series is a set of 262,144 bit, ultraviolet-
light erasable, electrically programmable read-only
memories. These devices are fabricated using power-saving
CMOS technology for high speed and simple interface with
MOS and bipolar circuits. All inputs (including program data
inputs) can be driven by Series 54 TTL circuits without the
use of external pullup resistors. Each output can drive one
Series 54 TTL circuit without external resistors. The data
outputs are 3-state for connecting multiple devices to a
common bus. The SMJ27C256 is pin-compatible with
28-pin 256K ROMs and EPROMs. It is offered in a 600mil
dual-in-line ceramic package (J suffix) and a 450 x 550 mil
ceramic LCC (ECA suffix) rated for operation from -55°C to 125°C.
Because this EPROM operates from a single 5V supply (in
the read mode), it is ideal for use in microprocessor-based
systems. One other supply (13V) is needed for programming.
All programming signals are TTL level. This device is
programmable by the SNAP! Pulse programming algorithm.
The SNAP! Pulse programming algorithm uses a VPP of 13V
and a VCC of 6.5V for a nominal programming time of four
seconds. For programming outside the system, existing
EPROM programmers can be used. Locations can be
programmed singly, in blocks, or at random.
FUNCTIONAL BLOCK DIAGRAM*
EPROM 32,768 x 8
10
A0
A1
A2
A3
A4
A5
A6
A7
A8
9
8
7
6
5
4
11
12
13
15
16
17
18
19
DQ0
DQ1
DQ2
DQ3
DQ4
DQ5
DQ6
DQ7
A
A
A
A
A
A
A
A
25
24
21
0
A
A9
32,767
A10
A11
A12
A13
A14
E\
23
2
26
27
14
20
22
[PWR DWN]
&
G\
EN
* This symbol is in accordance with ANSI/IEEE std 91-1984 and IEC Publication 617-12.
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
SMJ27C256/AS27C256
Rev. 2.5 10/03
2
MICROSS [ MICROSS COMPONENTS ]
