bq4024

The CMOS bq4024 is a nonvolatile 2,097,152-bit static RAM organized as 131,072 words by 16 bits. The integral control circuitry and lithium energy source provide reliable nonvolatility coupled with the unlimited write cycles of standard SRAM.

The control circuitry constantly monitors of bq4024 the single 5V supply for an out-of-tolerance condition. When VCC falls out of tolerance, the SRAM is unconditionally writeprotected to prevent an inadvertent write operation.

At this time the integral energy source is switched on to sustain the memory until after VCC returns valid. The bq4024 uses extremely low standby current CMOS SRAMs, coupled with small lithium coin cells to provide nonvolatility without long write-cycle times and the write-cycle limitations associated with EEPROM. The bq4024 requires no external circuitry and is compatible with the industry-standard 2Mb SRAM pinout.