BQ2204A

The BQ2204A from Texas Instruments is a CMOS SRAM Non-volatile Controller Unit that facilitates the conversion of standard CMOS SRAM into nonvolatile read/write memory. It is engineered for 3-volt battery-backup applications, offering essential power monitoring and switching capabilities.

This controller unit monitors the 5V VCC input and automatically forces the four conditioned chip-enable outputs inactive when an out-of-tolerance condition is detected. This write-protects up to four banks of SRAM during power failures. During such events, external SRAMs are switched from the VCC supply to one of two 3V backup supplies. Upon subsequent power-up, the SRAMs remain write-protected until a power-valid condition is re-established.

Key features include a 2-input decoder for transparently selecting one of up to four SRAM banks during power-valid operation. It boasts a chip-enable propagation delay of less than 10ns and supports 5% or 10% supply operation. The device is available in a 16-pin Narrow DIP or SOIC package, suitable for various board designs.

The BQ2204A is ideal for applications requiring data retention in volatile memory during power interruptions, such as data logging, configuration storage, and real-time clock backup.