The LTC694-3.3/LTC695-3.3 provide complete 3.3V power supply monitoring and battery control functions. These include power-on reset, battery back-up, RAM write protection, power failure warning and watchdog timing. The devices are pin compatible upgrades of the LTC694/ LTC695 that are optimized for 3.3V systems. Operating power consumption has been reduced to 0.6mW (typical) and 3W maximum in battery back-up mode. Microprocessor reset and memory write protection are provided when the supply falls below 2.9V. The RESET output is guaranteed to remain logic low with VCC as low as 1V. The LTC694-3.3/LTC695-3.3 power the active RAMs with a charge pumped NMOS power switch to achieve low dropout and low supply current. When primary power is lost, auxiliary power, connected to the battery input pin, powers the RAMs in standby through an efficient PMOS switch.