X28C256
256K
X28C256
32K x 8 Bit
5 Volt, Byte Alterable E2PROM
FEATURES
DESCRIPTION
2
• Access Time: 200ns
• Simple Byte and Page Write
— Single 5V Supply
—No External High Voltages or V Control
Circuits
— Self-Timed
The X28C256 is an 32K x 8 E PROM, 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-
widememories,compatiblewithindustrystandardRAMs.
PP
—No Erase Before Write
—No Complex Programming Algorithms
—No Overerase Problem
• Low Power CMOS:
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.
—Active: 60mA
—Standby: 200µA
• Software Data Protection
— Protects Data Against System Level
Inadvertent Writes
• High Speed Page Write Capability
™
• Highly Reliable Direct Write Cell
2
Xicor E PROMs are designed and tested for applica-
— Endurance: 100,000 Write Cycles
— Data Retention: 100 Years
• Early End of Write Detection
— DATA Polling
tions requiring extended endurance. Inherent data re-
tention is greater than 100 years.
—Toggle Bit Polling
PIN CONFIGURATION
LCC
PLCC
PLASTIC DIP
CERDIP
FLAT PACK
SOIC
TSOP
A
A
A
I/O
I/O
I/O
1
2
3
4
5
6
7
8
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
A
A
A
A
A
A
A
NC
V
NC
2
1
0
0
1
2
3
4
5
6
7
12
14
A14
1
28
27
26
25
24
23
22
21
20
19
18
17
16
15
V
CC
4
3
2
1
32 31 30
A
2
WE
12
A
A
A
A
A
A
A
5
6
7
8
9
29
28
27
26
25
24
23
22
21
A
A
A
6
5
4
3
2
1
0
8
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
3
A
13
9
4
A
8
A
9
NC
11
5
V
SS
NC
NC
OE
A
X28C256
6
A
9
11
X28C256
CC
I/O
10
11
12
13
14
15
16
7
OE
3
4
5
6
7
X28C256
I/O
I/O
I/O
I/O
WE
10
11
12
13
10
8
A
10
A
A
A
A
13
8
9
CE
I/O
9
CE
NC
7
10
11
12
13
14
I/O
7
I/O
6
I/O
5
I/0
4
CE
11
I/O
I/O
0
6
A
I/O
0
I/O
1
I/O
2
OE
10
14 15 16 17 18 19 20
3855 ILL F23
V
I/O
3
SS
3855 FHD F03
3855 FHD F02
© Xicor, Inc. 1991, 1995 Patents Pending
3855-1.9 8/1/97 T1/C0/D8 EW
Characteristics subject to change without notice
1
XICOR [ XICOR INC. ]
