DS2227 Datasheet, PDF (1/10 Pages) Dallas Semiconductor – Flexible NV SRAM Stik

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DS2227
Flexible NV SRAM Stik
FEATURES
Flexibly organized as 128k x 32, 256k x 16,
or 512k x 8 bits
Data retention >10 years in the absence of
V_CC
Nonvolatile circuitry transparent to and
independent from host system
Automatic write protection circuitry
safeguards against data loss
Separate chip enables allow access by byte,
word, or long word
Fast access times: 70 ns, 100 ns, or 120 ns
Unlimited write cycles
Read cycle time equals write cycle time
Employs popular JEDEC standard 72-position
SIMM connection scheme
Lithium energy source is electrically
disconnected to retain freshness until power is
applied for the first time
PIN ASSIGNMENT
72-Pin SIP STIK
DESCRIPTION
The DS2227 Flexible NV SRAM Stik is a self-contained 4,194,304-bit nonvolatile static RAM which can
be flexibly organized as 128k x 32 bits, 256k x 16 bits, or 512k x 8 bits. The nonvolatile memory contains
all necessary control circuitry and lithium energy sources to maintain data integrity in the absence of
power for more than 10 years. The DS2227 employs the popular JEDEC standard 72-position SIMM
connection scheme requiring no additional circuitry.
OPERATION
The DS2227 Flexible NV SRAM Stik is used like any standard static RAM. All nonvolatile circuitry is
transparent to the user. The flexibility of the part is achieved by providing separate read, write, and chip
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