BQ2205LY

用于双 SRAM 内存组的电池备份监控器

The CMOS bq2205 SRAM non-volatile controller with reset provides all the necessary functions for converting one or two banks of standard CMOS SRAM into non-volatile read/write memory.

A precision comparator monitors the 3.3-V VCC input for an out-of-tolerance condition. When out-of-tolerance is detected, the two conditioned chip-enable outputs are forced inactive to write-protect both banks of SRAM.

Power for the external SRAMs, VOUT, is switched from the VCC supply to the battery-backup supply as VCC decays. On a subsequent power-up, the VOUT supply is automatically switched from the backup supply to the VCC supply. The external SRAMs are write-protected until a power-valid condition exists. The reset output provides power-fail and power-on resets for the system. During power-valid operation, the input decoder, A, selects one of two banks of SRAM.

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Power Monitoring and Switching for Non-Volatile Control of SRAMs

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Input Decoder Allows Control of 1 or 2 Banks of SRAM

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Write-Protect Control

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3-V Primary Cell Input

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3.3-V Operation

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Reset Output for System Power-On Reset

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Less than 20-ns Chip Enable Propagation Delay

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Small 16-Lead TSSOP Package

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APPLICA ONS

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NVSRAM Modules

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Point-of-Sale Systems

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Facsimile, Printers and Photocopiers

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Internet Appliances

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Servers

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Medical Instrumentation and Industrial Products