AOZ1282CI

The AOZ1282CI is a high-efficiency, easy-to-use 1.2A buck regulator from Alpha & Omega Semiconductor’s EZBuck product line. It operates from a wide 4.5V to 36V input voltage range and provides up to 1.2A of continuous output current with adjustable output voltage down to 0.8V. The device uses current-mode PWM control with fixed 450kHz switching frequency and internal compensation, simplifying external component selection. An internal 420mΩ NMOS high-side switch handles power conversion, while an external Schottky diode serves as the freewheeling element. The device features 1.5ms internal soft start to limit inrush current, cycle-by-cycle overcurrent protection, short-circuit protection with auto-restart, and thermal shutdown. The SOT23-6L package enables compact PCB layouts.

The AOZ1282CI uses a current-mode PWM control architecture with fixed 450kHz switching frequency. The internal error amplifier compares the FB pin voltage (sensed from the output resistor divider) with the 800mV internal reference and generates a control signal. This control signal, combined with the current sense signal from the internal NMOS, determines the on-time of the high-side switch via the PWM comparator. During each switching cycle, the NMOS turns on and current flows through the inductor to the output and load. When the NMOS turns off, the inductor current freewheels through the external Schottky diode. The bootstrap capacitor (between BST and LX pins) provides the gate drive voltage for the NMOS. Cycle-by-cycle current limiting protects against overloads.

• 12V/24V POL: Step-down from industrial bus voltages to 3.3V/5V logic rails
• Telecom Equipment: 24V/48V to low-voltage conversion in networking racks
• LCD Displays: Panel power supply from 12V or 24V input
• Set-Top Boxes: Compact buck converter for cable and satellite receivers
• Industrial Sensors: Wide input range suits variable industrial power supplies