AP61100/AP61102Pin DescriptionsPin NamePin NumberFunction Feedback sensing terminal for the output voltage. Connect this pin to the resistive divider of the output. FB 1 See Setting the Output Voltage section for more details. GND 2 Power Ground. Power Input. VIN supplies the power to the IC as well as the step-down converter power MOSFETs. Drive VIN with a VIN 3 2.3V to 5.5V power source. Bypass VIN to GND with a suitably large capacitor to eliminate noise due to the switching of the IC. See Input Capacitor section for more details. Power Switching Output. SW is the switching node that supplies power to the output. Connect the output LC filter SW 4 from SW to the output load. Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn on the regulator and low to EN 5 turn it off. EN is used to program the Operation Mode (PFM or PWM). See Enable section for more details. OUT Output Voltage Power Rail. Connect OUT to the output load. (AP61100) 6 PG Power-Good. Open drain power-good output that is pulled to GND when the output voltage is out of its regulation (AP61102) limits or during soft-start.