BQ2204A

用于 4 SRAM 内存组的 SRAM 非易失性控制器 IC

The CMOS bq2204A SRAM Non-volatile Controller Unit provides all necessary functions for converting up to four banks of standard CMOS SRAM into nonvolatile read/write memory.

A precision comparator monitors the 5V VCC input for an out-of-tolerance condi-tion. When out-of-tolerance is detected, the four conditioned chip-enable outputs are forced inactive to write-protect up to four banks of SRAM.

During a power failure, the external SRAMs are switched from the VCC supply to one of two 3V backup sup-plies. On a subsequent power-up, the SRAMs are write-protected until a power-valid condition exists.

During power-valid operation, a two-input decoder transparently selects one of up to four banks of SRAM.

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Power monitoring and switching for 3-volt battery-backup applications

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Write-protect control

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2-input decoder for control of up to 4 banks of SRAM

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3-volt primary cell inputs

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Less than 10ns chip-enable propagation delay

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5% or 10% supply operation