AMS4123 Monolithic 2A BUCK CONVERTER + 1A LDO IN SO-8 is a switching regulator from Advanced Monolithic Systems, Inc. with 2A output power, 1A LDO output power, 300KHz switching frequency, internal soft start, zero current shutdown, 500mV maximum dropout.
The AMS4123 combines a 2 A asynchronous buck converter and a 1 A low‑dropout regulator (LDO) in a single SO‑8 EDP package. It includes internal compensation, a soft‑start circuit, hiccup current limit, and thermal shutdown that protects both sections. The device operates at a typical 300 kHz switching frequency and offers adjustable output voltages from 0.6 V to 5 V in 100 mV steps.
Typical applications include audio power amplifiers, portable computers, consumer electronics such as DVD/Blue‑ray writers, LCD TVs and monitors, distributed power systems, battery chargers, and as a pre‑regulator for linear regulators. The datasheet provides pin descriptions, absolute maximum ratings, electrical characteristics, typical performance curves, and package dimensions for designers.
| Switching regulator output current | 2 A |
|---|---|
| LDO output current | 1 A |
| Switching frequency | 300 kHz |
| LDO dropout voltage | 350 mV |
| Efficiency (switching regulator) | 88 % |
| Maximum duty cycle | 99 % |
| Enable threshold (switching section) | 2.0 V |
| Enable threshold (LDO section) | 2.5 V |
The switching regulator can deliver up to 2 A of output current.
Applying a voltage greater than 2.5 V to the EN pin enables the LDO section, while a voltage above 2 V enables the switching regulator.
The device typically operates at a switching frequency of 300 kHz.
The LDO has a typical dropout voltage of 350 mV.