The ADM8690 is available in 8-lead PDIP and SOIC packages and provides the following functions： 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. Reset pulse if the optional watchdog timer is not toggled within a specified time. 4. 1.3 V threshold detector for power-fail warning， low battery detection， or to monitor a power supply other than 5 V. The ADM8691 and ADM8695 are available in 16-lead PDIP and small outline packages （including TSSOP） 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.