Diodes Incorporated AP3928S-13

Overview

AP3928S-13 from Diodes Incorporated is a universal AC-input (85–300VAC), non-isolated buck-type power switcher integrating a 700V MOSFET, delivering up to 600mA rated output current, 10W output power, and <30mW no-load consumption. It targets cost-sensitive, low-noise auxiliary/standby supplies in home appliances and IoT edge devices using single-winding inductors.

For engineers reviewing the AP3928S-13 datasheet, AP3928S-13 pinout, AP3928S-13 application, or AP3928S-13 equivalent, key selection criteria include its adaptive frequency/peak-current light-load efficiency optimization, integrated OLP/SCP/OTP/open-loop protection, SO-8 package thermal performance (θJA = 76°C/W), and VCC auto-restart fault recovery behavior.

Technical Context

The AP3928S-13 implements a primary-side regulated buck controller with internal 700V MOSFET, operating in discontinuous conduction mode (DCM) or critical conduction mode (CCM). Its feedback loop uses FB pin voltage (2.5V typical threshold) derived from output-sampling capacitor C5 to regulate output voltage via resistor divider (R_UP/R_DOWN).

Startup employs an 8-stage soft-start reducing minimum OFF-time from 52.4µs to 13µs; under load, switching frequency and peak current scale inversely-e.g., f_SW drops from ~60kHz at full load to ~15kHz at 10% load, while I_PK decreases from 1.1A to ~150mA-to suppress audible noise and maintain >75% efficiency down to 10mW load.

Key Specifications

Pinout & Package

AP3928S-13 is housed in an SO-8 (Standard) surface-mount package with exposed thermal pad (not electrically connected), JEDEC MS-012AC compliant, matte tin-plated leads, and moisture sensitivity level 3.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar universal-input buck switcher applications.

Compared with MP174G-13-Z and LNK3206P, AP3928S-13 uniquely combines non-isolated buck simplicity, adaptive efficiency down to milliwatt loads, and SO-8 thermal performance-making it optimal for cost-constrained, space-limited, and acoustic-sensitive auxiliary power in Class II consumer and industrial equipment.

Availability

AP3928S-13 is available at Aetrix Electronics and suitable for smart home appliances, IoT edge sensors, and industrial control panels requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant manufacturing.

Supply support for AP3928S-13 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global semiconductor manufacturer specializing in discrete, analog, and mixed-signal ICs, with emphasis on power management, signal integrity, and connectivity solutions.

The AP3928 belongs to Diodes' AC-DC power switcher product line, engineered specifically for non-isolated, low-cost, low-noise auxiliary power in consumer and industrial applications where safety isolation is not mandated.

FAQ

What is the maximum recommended output power for AP3928S-13 in SO-8 package?

The AP3928S-13 is rated for up to 10W output power under typical conditions (85–265VAC input, 25°C ambient, adequate PCB copper area). Derating is required above +85°C ambient due to θ_JA = 76°C/W; at +105°C, max sustainable output drops to ~6.5W to maintain T_J ≤ 150°C. Thermal design must use ≥1in² 2oz copper pour under the exposed pad region.

How does the AP3928S-13 achieve <30mW no-load consumption?

It achieves <30mW no-load consumption through three mechanisms: (1) ultra-low VCC quiescent current (136µA typ.), (2) automatic HV regulator disable once VCC reaches 9V, and (3) optional auxiliary VCC supply via resistor R5 from output to VCC, which bypasses the internal HV current source entirely during regulation-eliminating standby losses from the 700V startup circuit.

Can AP3928S-13 drive a 24V output with 600mA load?

Yes-AP3928S-13 supports output voltages from 5V to 24V using standard resistor divider feedback (R_UP/R_DOWN). At 24V/600mA (14.4W), operation remains within its 10W rating only if input voltage is limited to ≤200VAC and thermal design sustains junction temperature ≤135°C; for full 24V/600mA, use derated input (e.g., 115VAC) or verify thermal margin with actual board layout.

What happens during open-loop fault condition?

When FB voltage falls below 0.3V (V_OLD)-indicating loss of feedback path-the AP3928S-13 immediately stops switching, discharges VCC via I_{CC_LATCH} (26µA typ.), and waits until VCC drops to 4.5V before restarting the HV charge cycle. This prevents uncontrolled output overvoltage and provides safe, bounded fault recovery without external latch circuitry.