APPLICATION NOTE
A V A I LA B L E
AN3 • AN7 • AN8 • AN15• AN16 • AN25 • AN29
• AN30 • AN35 • AN36 • AN39 • AN56 • AN69
X24C44
256 Bit
16 x 16 Bit
Serial Nonvolatile Static RAM
DESCRIPTION
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The Xicor X24C44 is a serial 256 bit NOVRAM featuring a static RAM configured 16 x 16, overlaid bit-by-bit
with a nonvolatile EEPROM array. The X24C44 is fabricated with Xicor’s Advanced CMOS Floating Gate
technology.
O
bs
CE (1)
DI (3)
SK (2)
REV 1.0 6/22/00
du
c
ro
E
R
AL
L
ST
Column
Decode
EC
Static
RAM
256-Bit
Row
Decode
Instruction
Register
Instruction
Decode
Nonvolatile
EEPROM
O
ol
et
BLOCK DIAGRAM
R
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Xicor NOVRAMs are designed for unlimited write operations to RAM, either from the host or RECALLs from
EEPROM and a minimum 1,000,000 STORE operations. Inherent data retention is specified to be greater
than 100 years.
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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 operation (RAM data to EEPROM) is completed in 5ms or less and a RECALL operation
(EEPROM data to RAM) is completed in 2µs or less.
e
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Advanced CMOS version of Xicor’s X2444
16 x 16 organization
Single 5V supply
Ideal for use with single chip microcomputers
—Static timing
—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 maximum
—Standby current: 50µA maximum
8-lead PDIP, Cerdip, and 8-lead SOIC packages
High reliability
—STORE cycles: 1,000,000
—Data retention: 100 years
t
FEATURES
Control
Logic
RECALL (6)
STORE (7)
DO (4)
4-Bit
Counter
www.xicor.com
Characteristics subject to change without notice.
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