View apx803 datasheet:

APX803/D 3-PIN MICROPROCESSOR RESET CIRCUIT Description Pin Assignments The APX803/D is used for microprocessor (µP) supervisory ( Top View ) circuits to monitor the power supplies in µP and digital systems. They provide excellent circuit reliability and low cost 1 GND by eliminating external components and adjustments when used with +5V, +3.3V, +3.0V powered circuits. APX803 3 VCC These circuits perform a single function: they assert a reset 2 2 RESET signal on power up and whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for a SOT23 fixed period of time after VCC has risen above the reset threshold. For the APX803D this period is a minimum of 1ms while for other APX803 variants it is at least 140ms. The reset co