A
PPLICATION
N
OTES
A V A I L A B L E
AN3 • AN7 • AN8 • AN15 • AN16 • AN25 • AN29
• AN30 • AN35 • AN36 • AN39 • AN56 • AN69
X24C45
256 Bit
X24C45
Serial AUTOSTORE™ NOVRAM
16 x 16 Bit
FEATURES
DESCRIPTION
The Xicor X24C45 is a serial 256 bit NOVRAM featuring
a static RAM configured 16 x 16, overlaid bit-by-bit with
a nonvolatile E
2
PROM array. The X24C45 is fabricated
with Xicor’s Advanced CMOS Floating Gate technology.
The Xicor NOVRAM design allows data to be transferred
between the two memory arrays by means of software
commands or external hardware inputs. A store opera-
tion (RAM data to E
2
PROM) is completed in 5ms or less
and a recall operation (E
2
PROM data to RAM) is com-
pleted in 2µs or less.
The X24C45 also includes the AUTOSTORE feature, a
user selectable feature that automatically performs a
store operation when V
CC
falls below a preset threshold.
Xicor NOVRAMs are designed for unlimited write opera-
tions to RAM, either from the host or recalls from E
2
PROM
and a minimum 1,000,000 store operations. Inherent data
retention is specified to be greater than 100 years.
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AUTOSTORE™ NOVRAM
—Automatically Performs a Store Operation
Upon Loss of V
CC
Single 5 Volt Supply
Ideal for use with Single Chip Microcomputers
—Minimum I/O Interface
—Serial Port Compatible (COPS™, 8051)
—Easily Interfaced to Microcontroller Ports
Software and Hardware Control of Nonvolatile
Functions
Auto Recall on Power-Up
TTL and CMOS Compatible
Low Power Dissipation
—Active Current: 10mA
—Standby Current: 50
µ
A
8-Lead PDIP and 8-Lead SOIC Packages
High Reliability
—Store Cycles: 1,000,000
—Data Retention: 100 Years
FUNCTIONAL DIAGRAM
NONVOLATILE
2
E PROM
ROW
DECODE
STATIC
RAM
256-BIT
R
EC
AL
L
ST
O
R
E
CONTROL
LOGIC
RECALL (6)
AS (7)
CE (1)
DI (3)
SK (2)
INSTRUCTION
REGISTER
COLUMN
DECODE
DO (4)
INSTRUCTION
DECODE
4-BIT
COUNTER
3833 FHD F01
AUTOSTORE™ NOVRAM is a trademark of Xicor, Inc.
COPS is a trademark of National Semiconductor Corp.
© Xicor, Inc. 1991, 1995, 1996 Patents Pending
3833-1.5 6/10/96 T3/C3/D0 NS
1
Characteristics subject to change without notice