Alpha & Omega Semiconductor Inc. AOZ1324DI-02

Overview

AOZ1324DI-02 from Alpha and Omega Semiconductor is a latch-off high-side protection switch with True Reverse Current Blocking (TRCB), 32 mΩ typical R_ON, 3.4–22 V input range, and integrated over-voltage, under-voltage, thermal, and short-circuit protection - designed for USB Type-C PD power path control in docking stations and portable computing systems.

For engineers reviewing the AOZ1324DI-02 datasheet, pinout, applications, or equivalent options, key selection considerations include fault recovery behavior (latch-off vs. auto-restart), programmable OVP threshold via POVP resistor, TRCB activation at 26 mV V_OUT–V_VIN, soft-start timing control via external CSS capacitor, and DFN-12 thermal pad layout requirements.

Technical Context

The AOZ1324DI-02 implements dual back-to-back N-channel MOSFETs to enable bidirectional blocking: it prevents reverse current flow when V_OUT > V_VIN by turning off within 500 ns of detecting ≥26 mV differential, and isolates input from output during shutdown with <35 µA quiescent current. Its control logic enforces latch-off fault recovery - only toggling ENB or cycling VIN clears FLTB and re-enables the switch.

Protection functions are independently monitored: UVLO triggers below 3.35 V (with 300 mV hysteresis), OVP activates at user-selectable thresholds (5.8 V with POVP open or 24 V with POVP grounded), and thermal shutdown engages at 140 °C (30 °C hysteresis). All protections assert open-drain FLTB low, requiring external pull-up for system-level fault signaling.

Key Specifications

Pinout & Package

AOZ1324DI-02 is housed in a thermally enhanced 3 mm × 3 mm DFN-12L package with exposed thermal pad (EXP), rated for –40 °C to +85 °C ambient operation. The EXP pad must be soldered to a floating copper thermal plane with multiple vias for effective heat dissipation; electrical isolation from GND or other nets is mandatory.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS22975DQAR and RT9711CGJ5, AOZ1324DI-02 uniquely combines latch-off fault handling, 3.4–22 V operation, True Reverse Current Blocking, and programmable OVP - making it the only option qualified for USB-C PD power path isolation in docking stations and portable monitors.

Availability

AOZ1324DI-02 is available at Aetrix Electronics and suitable for USB-C docking stations, portable monitors, notebook internal power routing, and USB-C dongles requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for AOZ1324DI-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 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 AOZ1324DI product line delivers ECPower™-optimized high-side switches for USB-C PD and portable computing applications, emphasizing low R_ON, integrated protection, and compact DFN packaging for space-constrained designs.

FAQ

What fault conditions trigger the FLTB pin on AOZ1324DI-02?

The FLTB pin on AOZ1324DI-02 is asserted low during five confirmed fault conditions: input under-voltage (VIN < 3.35 V), input over-voltage (exceeding programmed OVP threshold), true reverse current (VOUT > VIN by ≥26 mV), thermal shutdown (junction temperature ≥140 °C), or output short-circuit. Each condition disables the power switch and pulls FLTB low until ENB is toggled or VIN is cycled - consistent with the latch-off behavior specified for AOZ1324DI-02.

How does AOZ1324DI-02 differ from AOZ1324DI-01 in fault recovery behavior?

AOZ1324DI-02 implements latch-off fault recovery: once a fault occurs, the switch remains disabled and FLTB stays low until ENB is toggled or VIN is power-cycled. In contrast, AOZ1324DI-01 auto-restarts every 64 ms after fault clearance. This distinction is hard-coded per variant - AOZ1324DI-02 cannot be configured to auto-restart, and its datasheet explicitly states "toggle enable to restart the device and clear fault indicator" as the sole recovery method.

What is the minimum external capacitor value required for stable soft-start operation of AOZ1324DI-02?

AOZ1324DI-02 requires an external soft-start capacitor (CSS) connected between SS pin and GND to control VOUT ramp time. While no absolute minimum value is specified, typical design uses 1 nF to 5.6 nF. With CSS = 1 nF, turn-on rise time is ~220 µs (VIN = 20 V); with CSS = 5.6 nF, it extends to ~1.2 ms. Values below 1 nF may cause excessive inrush current; values above 10 nF risk violating the 300 mV soft-start dropout limit if output capacitance is large.

Can AOZ1324DI-02 be used in 5 V-only applications, and what OVP threshold applies?

Yes, AOZ1324DI-02 operates down to 3.4 V input, making it suitable for 5 V-only applications. When POVP is left open (no resistor), the OVP threshold defaults to 5.8 V - providing 0.8 V headroom above nominal 5 V, which aligns with USB 2.0/3.x VBUS tolerance. This configuration avoids false trips during normal 5 V regulation ripple while still protecting against sustained overvoltage events.

What is the recommended PCB layout practice for the exposed thermal pad (EXP) of AOZ1324DI-02?

The EXP pad of AOZ1324DI-02 must be soldered to a dedicated floating copper thermal pad on the PCB - electrically isolated from GND, VIN, or VOUT. Use ≥6 thermal vias (0.3 mm diameter) connecting the pad to inner-layer copper planes, and maximize pad area to match the 2.5 mm × 2.5 mm EXP footprint. Avoid routing traces or placing components over the thermal pad area, and ensure solder paste coverage is ≥80% to guarantee mechanical integrity and thermal performance.