BQ2205LYPW

The precision comparator in the SRAM non-volatile controller detects an out-of-tolerance condition for the VCC input. When this condition is detected, the two conditioned chip-enable outputs are forced inactive to write-protect both banks of SRAM. Additionally, power for the external SRAMs is switched from the VCC supply to the battery-backup supply as VCC decays. The external SRAMs remain write-protected until a power-valid condition exists. This ensures the data integrity of the SRAM during power fluctuations.

Some of the applications listed for the power monitoring and switching device described in the PDF are NVSRAM modules, point-of-sale systems, facsimile, printers and photocopiers, internet appliances, servers, medical instrumentation, and industrial products.

The primary function of the CMOS bq2205 SRAM non-volatile controller is to provide all the necessary functions for converting one or two banks of standard CMOS SRAM into non-volatile read/write memory. It includes power monitoring and switching for non-volatile control of SRAMs, write-protect control, a reset output for system power-on reset, and an input decoder that allows control of 1 or 2 banks of SRAM. Additionally, it features a precision comparator to monitor the VCC input for an out-of-tolerance condition, and it switches power for the external SRAMs from the VCC supply to the battery-backup supply as VCC decays. The external SRAMs are write-protected until a power-valid condition exists, ensuring data integrity during power failures. The controller also provides a power-on reset for the system and allows access to the external RAM when the reset signal returns inactive. Furthermore, it includes a 3-V primary cell input for use with an external primary battery, such as a lithium-based battery. Overall, the CMOS bq2205 SRAM non-volatile controller serves to maintain data integrity and provide reliable non-volatile memory functionality for various applications.