The ADM691A/ADM693A/ADM800L/ADM800M 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 family of products provides an upgrade for the MAX691A/93A/800M family of products. All parts are available in 16-pin DIP and SO packages. The ADM691A is also available in a space-saving TSSOP package. The following functionality is provided： 1. Power-on reset output during power-up， power-down and brownout conditions. The circuitry 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 1.25 V threshold detector for power fail warning， low battery detection， or to monitor a power supply other than +5 V.