BQ2502MA [Texas Instruments]

The bq2502 is an integrated backup unit that provides power monitoring, backup supply, and switching for 3V battery backup applications. It features write-protect control, an input decoder for up to two SRAM banks, a 3-volt backup power output, and an internal 130mAh lithium-coin cell. The device provides a reset output for system power-on reset and has less than 10ns chip-enable propagation delay. It operates with 5% or 10% supply tolerance. The unit converts one or two banks of standard CMOS SRAM into nonvolatile read/write memory by switching power from VCC to the internal battery when VCC falls below a threshold, and automatically switching back when VCC is restored. It also provides write protection for external SRAMs during power failure and power-up sequences.