ANALOG DEVICES ADM709 datasheet

The ADM709 is a power supply monitor that generates a system reset during power-up, power-down, and brownout conditions. When VCC falls below the reset threshold, RESET goes low and holds the µP in reset. On power-up the RESET output is held low for 140 ms after VCC rises above the thresh- old. The RESET output remains operational with VCC as low as the reset threshold.