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.

FEATURES
■ Flexibly organized as 128k x 32, 256k x 16, or 512k x 8 bits
■ Data retention >10 years in the absence of VCC
■ 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