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X28C256 Datasheet, PDF (1/24 Pages) Xicor Inc. – 5 Volt, Byte Alterable E2PROM
X28C256
256K
X28C256
5 Volt, Byte Alterable E2PROM
32K x 8 Bit
FEATURES
• Access Time: 200ns
• Simple Byte and Page Write
— Single 5V Supply
—No External High Voltages or VPP Control
Circuits
— Self-Timed
—No Erase Before Write
—No Complex Programming Algorithms
—No Overerase Problem
• Low Power CMOS:
—Active: 60mA
—Standby: 200µA
• Software Data Protection
— Protects Data Against System Level
Inadvertent Writes
• High Speed Page Write Capability
• Highly Reliable Direct Write™ Cell
— Endurance: 100,000 Write Cycles
— Data Retention: 100 Years
• Early End of Write Detection
— DATA Polling
—Toggle Bit Polling
PIN CONFIGURATION
DESCRIPTION
The X28C256 is an 32K x 8 E2PROM, fabricated with
Xicor’s proprietary, high performance, floating gate
CMOS technology. Like all Xicor programmable non-
volatile memories the X28C256 is a 5V only device. The
X28C256 features the JEDEC approved pinout for byte-
wide memories, compatible with industry standard RAMs.
The X28C256 supports a 64-byte page write operation,
effectively providing a 78µs/byte write cycle and en-
abling the entire memory to be typically written in less
than 2.5 seconds. The X28C256 also features DATA
and Toggle Bit Polling, a system software support
scheme used to indicate the early completion of a write
cycle. In addition, the X28C256 includes a user-optional
software data protection mode that further enhances
Xicor’s hardware write protect capability.
Xicor E2PROMs are designed and tested for applica-
tions requiring extended endurance. Inherent data re-
tention is greater than 100 years.
PLASTIC DIP
CERDIP
FLAT PACK
SOIC
LCC
PLCC
A14 1
A12 2
28
VCC
27 WE
4 3 2 1 32 31 30
A2
1
A1
2
A0
3
A7 3
A6 4
26
A13
25
A8
A6 5
A5 6
29 A8
28 A9
I/O0
4
I/O1
5
I/O2
6
A5 5
24
A9
A4 6
23
A11
A3
7
22
X28C256
OE
A2 8
21
A10
A1 9
20 CE
A4 7
A3 8
A2 9
A1 10
A0 11
X28C256
27 A11
NC
7
26 NC
VSS
8
NC
9
25 OE
I/O3
10
24 A10
23 CE
I/O4
I/O5
I/O6
11
12
13
A0 10
I/O0 11
19
I/O7
18
I/O6
NC 12
22 I/O7
I/O0
13
21
14 15 16 17 18 19 20
I/O6
I/O7
CE
A10
14
15
16
I/O1 12
17
I/O5
I/O2 13
16
I/04
VSS 14
15
I/O3
3855 FHD F03
3855 FHD F02
TSOP
X28C256
32
A3
31
A4
30
A5
29
A6
28
A7
27
A12
26
A14
25
NC
24
VCC
23
NC
22
WE
21
A13
20
A8
19
A9
18
A11
17
OE
3855 ILL F23
© Xicor, Inc. 1991, 1995 Patents Pending
3855-1.9 8/1/97 T1/C0/D8 EW
1
Characteristics subject to change without notice