The CMOS bq4016 is a nonvolatile 8,388,608-bit static RAM organized as 1,048,576 words by 8 bits. The integral control circuitry and lithium energy source provide reliable non-volatility coupled with the unlimited write cycles of standard SRAM. The control circuitry constantly monitors the single 5V supply for an out-of-tolerance condition. When VCC falls out of tolerance, the SRAM is unconditionally write-protected 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 bq4016 uses extremely low standby current CMOS SRAMs, coupled with a small lithium coin cell to provide nonvolatility without long write-cycle times and the write-cycle limitations associated with EEPROM. The bq4016 has the same interface as industry-standard SRAMs and requires no external circuitry.