Voltage Detector Supervises The Supervisors

Designed to support the supervisory circuits of microprocessors and microcontrollers, the APX803L micro-power voltage detector accurately monitors voltage levels and will generate a reset signal whenever a supply rail falls below a defined threshold. This function is required by systems such as computers, communications equipment, and portable battery-powered devices. The device’s low quiescent current also makes it viable for appliances like televisions when they operate in standby mode.


Requiring no external components, detection voltage level range is from 1.2V to 5.0V in 0.1V steps and threshold accuracy is ±1.5% while consuming 1 μA. Whenever the monitored VCC power supply rail drops below the chosen threshold, the device asserts a reset signal within 20 μs that is held until the supply rail recovers to a level above the threshold. The device’s reset pin provides an open-drain, active-low output with device ordering options that allow for delay times of 0 ms, 55 ms, 220 ms, or 450 ms.


The APX803L is available in 3-pin SOT23, SOT323, and SC59 packages, as well as a 5-pin SOT25 package, and supports drop-in replacements and original designs. If this has piques your interest and curiosity, you may want to peruse an APX803L DATASHEET.