Alpha & Omega Semiconductor Inc. AOZ1381DI-02

Overview

AOZ1381DI-02 from Alpha & Omega Semiconductor is a dual-mode USB Type-C Power Delivery protection switch integrating independent sink and source back-to-back N-channel MOSFETs in a single DFN-20L package. It delivers 5.5A continuous sink current (32mΩ R_ON) and 3.5A programmable source current (39mΩ R_ON), with latch-off fault recovery, TRCB in both modes, and support for Fast Role Swap (FRS) via FON pin - deployed in ultrabooks and portable devices requiring robust PD 3.0 compliance.

For engineers reviewing the AOZ1381DI-02 datasheet, pinout, applications, or equivalent options, this page provides verified electrical parameters, thermal shutdown behavior at 140°C, latch-off fault response per FLTB_SNK/FLTB_SRC flags, and design-critical timing values including t_FON = 50–100µs and t_{TRCB_SRC} = 600ns - all confirmed from AOS Rev. 1.1 datasheet.

Technical Context

The AOZ1381DI-02 implements two independent, back-to-back N-MOSFET power paths: sink mode (VBUS→VCHG, 3.4–22V, 5.5A cont.) with active-low ENB_SNK, programmable POVP (5.8V/24V), and adjustable soft-start via CSS; source mode (V5V→VBUS, 3.4–5.5V, up to 3.5A) with active-high EN_SRC, FON-controlled fast turn-on (50–100µs), and ILIM-set over-current protection.

Both paths feature True Reverse Current Blocking (TRCB): sink triggers at V_CHG − V_VBUS ≥ 44mV (startup) or ≥26mV (runtime); source triggers at V_VBUS − V_V5V ≥ 25mV with 65mV hysteresis. Fault reporting uses open-drain FLTB_SNK and FLTB_SRC pins, each independently pulled low for OVP, OCP, TRCB, or thermal shutdown (T_SD = 140°C, 30°C hysteresis).

Key Specifications

Pinout & Package

AOZ1381DI-02 is housed in a thermally enhanced 3mm × 5.2mm DFN-20L package with exposed thermal pad (EXP) electrically isolated and soldered to internal ground plane for optimal junction-to-board thermal transfer (θ_JA = 36°C/W on AOS evaluation board). The EXP pad serves as common drain node for sink switches and must be connected via multiple vias to floating copper layers.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar USB-C PD dual-path protection applications.

Compared with TPS65987D and FUSB302B, AOZ1381DI-02 delivers monolithic sink/source switching with embedded TRCB, latch-off fault recovery, and FRS-ready timing - reducing component count, PCB area, and firmware dependency while maintaining full USB-C PD 3.0 compliance.

Availability

AOZ1381DI-02 is available at Aetrix Electronics and suitable for ultrabooks, portable monitors, and USB-C docking stations requiring stable component supply, latch-off fault safety, and certified USB PD 3.0 dual-role power management.

Supply support for AOZ1381DI-02 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 & Omega Semiconductor (AOS) is a fabless power semiconductor company specializing in high-efficiency MOSFETs, power ICs, and USB-C PD solutions, with global manufacturing and test partnerships.

The AOZ1381DI product line delivers integrated USB-C PD protection switches optimized for space-constrained portable electronics, combining low-R_ON power FETs, intelligent fault management, and compliance with IEC 61000-4-2/4-5 and UL 62368-1.

FAQ

What is the key functional difference between AOZ1381DI-01 and AOZ1381DI-02?

The AOZ1381DI-02 implements latch-off fault recovery, meaning that once a fault (OVP, TRCB, thermal shutdown) occurs, the affected path remains disabled until ENB_SNK or EN_SRC is cycled. In contrast, AOZ1381DI-01 uses auto-recovery with 64ms restart interval. This makes AOZ1381DI-02 preferable for safety-critical or fault-isolation-sensitive designs where uncontrolled re-engagement could risk system integrity.

How does the AOZ1381DI-02 implement True Reverse Current Blocking in sink mode?

The AOZ1381DI-02 detects reverse current in sink mode by monitoring the voltage differential between VCHG and VBUS. At startup, it blocks if VCHG ≥ VBUS + 44mV; during normal operation, it triggers TRCB if VCHG ≥ VBUS + 26mV, turning off the sink switch within 500ns and pulling FLTB_SNK low. This prevents battery discharge into a pre-charged VBUS line - a critical requirement for dead-battery operation in notebooks.

What is the purpose of the FON pin on the AOZ1381DI-02, and how is it used in Fast Role Swap?

The FON pin on AOZ1381DI-02 disables internal soft-start and reduces source turn-on delay to 50–100µs, enabling compliance with USB PD Fast Role Swap timing requirements. To use it, FON must be driven high before asserting EN_SRC; if V5V > VBUS, the switch turns on immediately; if VBUS > V5V, TRCB holds the switch off until VBUS drops below V5V minus 40mV, then recovers in <80µs.

Can the AOZ1381DI-02 support both 5V and 20V sink operation, and what protections apply across that range?

Yes - the AOZ1381DI-02 supports sink operation from 3.4V to 22V on VBUS/VCHG, covering USB PD 5V, 9V, 15V, and 20V profiles. Across this range, it maintains UVLO (3.25V typ), OVLO (programmable 5.8V or 24V), TRCB (26mV runtime), and thermal shutdown (140°C). Its 28V absolute maximum rating on VBUS/VCHG ensures margin against transients during 20V PD negotiation.

How is current limiting configured for the source path of the AOZ1381DI-02?

Source current limiting on AOZ1381DI-02 is set via an external resistor R_ILIM connected between ILIM pin and GND. Using R_ILIM = 14.3kΩ yields 1.0A OCP threshold; 7.1kΩ gives 2.0A; 4.02kΩ gives 3.5A. The relationship is approximately I_LIM ≈ 14.3kΩ / R_ILIM (in kΩ) amps. A 1% tolerance resistor is recommended for accuracy, and FLTB_SRC pulls low after 10ms delay upon current exceedance.