Alpha & Omega Semiconductor Inc. AOZ13937DI-03

Overview

AOZ13937DI-03 from Alpha and Omega Semiconductor is a high-side smart protection switch with integrated back-to-back MOSFETs, designed for reverse-current blocking in USB Type-C PD power paths. It delivers 8 A continuous current, 20 mΩ typical R_ON at 20 V, 3.4–32 V input range, and auto-restart fault recovery. It serves as the primary power ORing and surge-protected VBUS switch in multi-port docking stations.

For engineers reviewing the AOZ13937DI-03 datasheet, pinout, applications, or equivalent options, this page provides verified functional context, thermal shutdown hysteresis (30 °C), IDTRCB regulation voltage (35 mV), soft-start programmability, and fault flag behavior specific to the -03 variant.

Technical Context

The AOZ13937DI-03 implements a dual-MOSFET high-side architecture with gate drive and charge pump control to enable true ideal diode operation. Its IDTRCB function actively regulates VIN–VOUT to 35 mV under light load and transitions to resistive conduction at higher currents, while the FLTB pin reports thermal shutdown and over-voltage faults via open-drain signaling.

It features programmable over-voltage lockout (33 V or 23 V threshold selectable via POVP pin), under-voltage lockout (3.35 V), and startup short-circuit protection with 64 ms auto-restart interval. Thermal shutdown activates at 140 °C with 30 °C hysteresis, enabling automatic recovery when junction temperature falls below ~110 °C.

Key Specifications

Pinout & Package

AOZ13937DI-03 is housed in a thermally enhanced DFN3x3-12L package (3 mm × 3 mm, 0.9 mm height) with exposed thermal pad (EXP) for direct PCB copper coupling. The 12-pin layout supports high-current routing and low-inductance grounding.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-side protection switch applications.

Compared with AOZ13937DI-04, the AOZ13937DI-03 offers faster system recovery after transient faults but requires careful thermal design due to repeated auto-restarts; versus TPS25942L, it delivers 78% higher continuous current and unique IDTRCB functionality essential for multi-source VBUS architectures.

Availability

AOZ13937DI-03 is available at Aetrix Electronics and suitable for USB-C docking stations, high-performance laptop power ORing, Thunderbolt 4 host protection, and USB PD EPR adapter output stages requiring stable component supply across production lifecycles.

Supply support for AOZ13937DI-03 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

Alpha and Omega Semiconductor (AOS) is a fabless power semiconductor company specializing in high-efficiency MOSFETs, power ICs, and advanced packaging for power conversion and protection.

The AOZ13937DI product line was developed to address reverse-current vulnerability and surge-current limitations in USB-C PD systems, delivering integrated protection with minimal external components and industry-leading SOA robustness.

FAQ

What is the key functional difference between AOZ13937DI-03 and AOZ13937DI-04?

The AOZ13937DI-03 implements auto-restart fault recovery: after thermal shutdown or over-voltage event, it automatically re-enables with soft-start once the fault condition clears. In contrast, AOZ13937DI-04 latches off permanently and requires ENB toggle or input power cycle to resume operation. This makes AOZ13937DI-03 suitable for unattended systems needing autonomous recovery, while AOZ13937DI-04 suits safety-critical applications requiring explicit operator intervention. Both share identical electrical specs and pinout.

How does the IDTRCB feature of AOZ13937DI-03 prevent reverse current in USB-C applications?

The AOZ13937DI-03 implements Ideal Diode True Reverse Current Blocking by actively regulating the voltage drop between VIN and VOUT to 35 mV under light load. If VOUT rises above VIN minus 35 mV-such as during hot-plug of a powered peripheral-the internal gate driver forces the back-to-back MOSFETs fully off, breaking the conduction path. This prevents any measurable reverse current flow regardless of VOUT voltage level, eliminating cross-port backfeed in multi-port docks and protecting upstream PD controllers from damage.

What is the recommended soft-start capacitor value for AOZ13937DI-03 with a 100 µF output capacitor and 6 A load?

For AOZ13937DI-03 driving a 100 µF output capacitor with a 6 A resistive load, the recommended soft-start capacitor (CSS) is 47 nF. This value balances inrush current control against SOA compliance: smaller values risk triggering startup short-circuit protection due to excessive dV/dt, while larger values extend ramp time beyond safe energy limits. Figure 6 in the AOZ13937DI-03 datasheet confirms 47 nF lies within the validated "CSS MAX with 6A LOAD" boundary for 100 µF COUT, ensuring reliable turn-on without MOSFET overstress.

Does AOZ13937DI-03 require external components for over-voltage protection?

No, AOZ13937DI-03 integrates programmable over-voltage protection without external comparators or references. The POVP pin accepts either a resistor divider from VIN to GND or a fixed DC voltage to select between two factory-trimmed thresholds: 33 V (if POVP < 1.25 V) or 23 V (if POVP > 1.4 V). The selected threshold is latched at enable time, and over-voltage detection triggers within 512 µs, pulling FLTB low and disabling the power switch. No external TVS or clamping diodes are needed for basic OVP compliance.

What thermal performance can be expected from AOZ13937DI-03 in a standard 4-layer PCB layout?

With proper layout-including full-soldering of the EXP thermal pad to ≥2 cm² of inner-layer copper connected via ≥8 thermal vias-AOZ13937DI-03 achieves R_th(J-C) = 2.5 °C/W and R_th(J-A) ≈ 36 °C/W. At 8 A continuous load and 20 V input, power dissipation is ~1.28 W (I²R), resulting in ~32 °C junction-to-ambient rise above board temperature. This allows reliable operation up to +93 °C ambient while maintaining T_J ≤ 125 °C, meeting requirements for enclosed laptop dock enclosures without forced airflow.