A family of four microprocessor supervisor analog ICs monitors the power supply of a processor to prevent it from misexecuting software instructions or enabling hardware incorrectly because of low supply voltages. The IMP809, IMP810, IMP811 and IMP812 ICs are available with six reset threshold options; accuracy is pegged at 1.5% or better.If the supply voltage drops below the chip-reset threshold, the ICs generate a reset signal to the microprocessor or microcontroller. This signal is maintained active for 140 ms after the supply goes back above the threshold voltage. The IMP809 and IMP810 reset signals are of opposite polarity. The IMP811 and IMP812 ICs add a manual reset input for pushbutton reset activation and also have opposite-polarity reset output signals.All four chips consume low current to support battery-powered systems. Supply currents are 15 µA maximum for the 4V, 4.38V and 4.63V threshold devices for 5V systems and 10 µA maximum for the 2.63V, 2.93V and 3.08V threshold devices for 3V systems.