General Description The G690/G691 are microprocessor (μP) supervisory circuits used to monitor the power supplies in μP and digital systems. They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with +5V, +3.3V, +3.0V- powered circuits. These circuits perform a single function: they assert a reset ** whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for at least 140ms after VCC has risen above the reset threshold. Reset thresholds suitable for operation with a variety of supply voltages are available. The G691L has an open-drain output stage, while the G690 have push-pull outputs. The G691L’s open-drain RESET output requires a pull-up resistor that can be connected to a voltage higher than VCC. The G690L have an active-low RESET output, while the G690H has an active-high RESET output. The reset comparator is designed to ignore fast transients on VCC, and the outputs are guaranteed to be in the correct logic state for VCC down to 1V. Low supply current makes the G690/G691 ideal for use in portable equipment. The G690/G691 are available in 3-pin SOT-23 and SC-70-3(SOT-323) packages.