The ADM690–ADM695 family of supervisory circuits offers complete single chip solutions for power supply monitoring and battery control functions in microprocessor systems. These functions include μP reset， backup battery switchover， watchdog timer， CMOS RAM write protection， and power failure warning. The complete family provides a variety of configurations to satisfy most microprocessor system requirements. The ADM690， ADM692 and ADM694 are available in 8-pin DIP packages and provide： 1. Power-on reset output during power-up， power-down and brownout conditions. The RESET output remains operational with VCC as low as 1 V. 2. Battery backup switching for CMOS RAM， CMOS microprocessor or other low power logic. 3. A reset pulse if the optional watchdog timer has not been toggled within a specified time. 4. A 1.3 V threshold detector for power fail warning， low battery detection， or to monitor a power supply other than +5 V. The ADM691， ADM693 and ADM695 are available in 16-pin DIP and small outline packages and provide three additional functions. 1. Write protection of CMOS RAM or EEPROM. 2. Adjustable reset and watchdog timeout periods. 3. Separate watchdog timeout， backup battery switchover， and low VCC status outputs.