Datasheet AP68255Q (Diodes) - 3

AP68255Q/AP68355Q Pin Descriptions Pin Name Pin Number Function
Analog ground is used for the control. Single point connection to the EPAD and the external Schottky diode power GND 1 ground plane for proper electrical/thermal operations. Power Input. VIN supplies the power to the IC, as well as the step-down converter switches. Drive VIN with a 5.5V to VIN 2 80V power source. Bypass VIN to GND with a suitably large capacitor to eliminate noise on the input to the IC. See Input Capacitor. 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 3 turn it off. Leave floating for automatic startup. The EN has a precision threshold of 1.25V for programing the UVLO. See Enable section for more details. NC 4, 6 Connect these NC pins to EPAD. Feedback Input. FB senses the output voltage and regulates it. Drive FB with a resistive divider connected to it from FB 5 the output voltage to this pin. The feedback regulation voltage is 1.2V. See “Setting the Output Voltage”. High-Side Gate Drive Boost Input. BST supplies the drive for the high-side N-Channel MOSFET with a 0.1µF or BST 7 greater capacitor from SW to BST to power the high side switch. Power Switching Output. SW is the switching node that supplies power to the output. Connect the output LC filter SW 8 from SW to the output load. Note that a capacitor is required from SW to BST to power the high-side switch. Heat dissipation path of die. Electrical connection to GND pin. Must be connected to ground plane on PCB for EPAD 9 proper operation and optimized thermal performance. AP68255Q/AP68355Q 3 of 19 April 2025 Document number: DS47151 Rev. 1 - 2
www.diodes.com
© 2025 Copyright Diodes Incorporated. All Rights Reserved.