AP1533 is a PWM control 1.8A step-down converter with low ripple power, high efficiency and excellent transient characteristics. The converter contains a reference voltage source, oscillation circuit, error amplifier and internal PMOS. The PWM control circuit is able to vary the duty ratio linearly from 0% to 99%. The converter also contains an error amplifier circuit as well as a soft-start circuit that prevents overshoot at startup. An enable function, an over current protect function and a short circuit protect function are built inside, and when OCP or SCP happens, the operation frequency will be reduced from 300KHz to 50KHz. Also, an internal compensation block is built in to minimum external component count. With the addition of an internal P-channel Power MOS, a coil, capacitors, and a diode connected externally, these ICs can function as step-down switching regulators. They serve as ideal power supply units for portable devices when coupled with mobile devices.
The AP1533 is a PWM‑controlled 1.8 A step‑down (buck) DC/DC converter that operates from 4 V to 23 V input and delivers up to 2 A peak output. It includes built‑in protection features such as under‑voltage lockout, current‑limit, thermal shutdown and soft‑start.
Typical applications include PC motherboards, LCD monitors, graphic cards, DVD‑Video players, telecom equipment and other peripheral devices. The datasheet details electrical characteristics, pin assignments, recommended component values, PCB layout guidance and ordering information.
| Input Voltage | 4 V to 23 V |
|---|---|
| Output Current | 1.8 A (typ) up to 2 A peak |
| Oscillation Frequency | 300 kHz typ. |
| Duty Ratio | 0 % to 99 % |
| Thermal Shutdown Threshold | 150 °C |
The AP1533 operates with an input voltage from 4 V to 23 V.
It provides a typical output current of 1.8 A and can reach up to 2 A peak.
The typical oscillation (switching) frequency is 300 kHz.
The device includes under‑voltage lockout, current‑limit protection, thermal shutdown and soft‑start functions.