Alpha & Omega Semiconductor Inc. AOZ8318DI

Overview

AoZ8318DI from Alpha & Omega Semiconductor is a dual-channel, low-capacitance, bi-directional TVS diode array designed for ESD protection of high-speed data lines including USB 2.0, HDMI, and DisplayPort interfaces; features 5.5V working voltage, 12A peak pulse current (8/20µs), and <0.5pF channel capacitance per line.

For engineers reviewing the AOZ8318DI datasheet, pinout, applications, or equivalent options, key selection criteria include channel-to-channel capacitance matching, IEC 61000-4-2 ±15kV contact ESD rating, low clamping voltage under transient stress, and DFN-10 (2.5×1.0mm) package compatibility with high-density PCB layouts.

Technical Context

The AOZ8318DI integrates two independent, matched TVS diode pairs in a single DFN-10 package, each pair configured as a bi-directional rail-to-rail clamp between I/O and V_CC/GND. It operates without bias supply and supports signal rates up to 480Mbps.

Designed for system-level ESD immunity, the device meets IEC 61000-4-2 Level 4 (±15kV contact, ±20kV air) and provides clamping voltages of ≤12V at 12A (8/20µs) on both I/O-to-GND and I/O-to-V_CC paths while maintaining sub-0.5pF line-to-line capacitance.

Key Specifications

Pinout & Package

AOZ8318DI is housed in a lead-free, halogen-free DFN-10 package (2.5mm × 1.0mm, 0.55mm height) with exposed thermal pad for enhanced power dissipation during ESD transients.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ESD protection applications.

Compared with RCLAMP0524P.TCT and ESD7L5.0DT5G, the AOZ8318DI delivers higher surge robustness (12A vs. 10A/3A), native dual-channel integration in DFN-10, and tighter capacitance matching-making it optimal for space-constrained, high-speed differential interface protection where layout reuse and signal fidelity are critical.

Availability

AOZ8318DI is available at Aetrix Electronics and suitable for USB 2.0 interface protection, HDMI 1.4 source port hardening, and DisplayPort 1.2a sink port safeguarding requiring stable component supply and consistent green material compliance.

Supply support for AOZ8318DI 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 MOSFETs, TVS diodes, and power ICs for efficiency-critical applications.

The AOZ8318DI belongs to AOS's ESD protection product line, engineered specifically for high-speed serial interface protection with emphasis on ultra-low capacitance, rail-to-rail clamping, and halogen-free packaging for consumer and industrial electronics.

FAQ

What is the maximum operating temperature range for the AOZ8318DI?

The AOZ8318DI is rated for operation from −40°C to +125°C ambient temperature. This extended range supports deployment in automotive infotainment head units and industrial display controllers where thermal cycling and enclosure heating are present. The DFN-10 package's thermal pad enhances heat dissipation during repetitive ESD events, helping maintain clamping performance across the full range. AOZ8318DI remains fully functional and compliant with IEC 61000-4-2 throughout this interval.

Does the AOZ8318DI require an external bias or control signal to function?

No, the AOZ8318DI operates passively and requires no external bias, enable signal, or configuration. It functions as a voltage-triggered clamp: conduction begins only when transient voltage exceeds the breakdown threshold (~7.5V), returning to high-impedance state once the event subsides. This zero-power, always-on behavior makes AOZ8318DI ideal for protecting battery-powered devices and low-power peripherals without affecting quiescent current or firmware design.

Can the AOZ8318DI be used to protect RS-485 or CAN bus lines?

The AOZ8318DI is not recommended for RS-485 or CAN bus protection. Its 5.5V working voltage and ~7.5V breakdown are too low for standard RS-485 common-mode ranges (±7V to ±12V) and CAN transceiver rails (typically 5V but with ±40V fault tolerance). Using AOZ8318DI on these buses risks premature clamping and signal distortion. For such applications, AOS offers dedicated solutions like AOZ8210 (for CAN) or AOZ8220 (for RS-485), which match the required voltage and surge ratings.

How does the AOZ8318DI's halogen-free status impact its reliability in high-humidity environments?

The AOZ8318DI complies with AOS Green Policy: bromine and chlorine content each <900ppm, total <1500ppm. This halogen-free formulation eliminates corrosive decomposition products under thermal stress or moisture exposure, significantly reducing risk of electrochemical migration and dendritic growth on PCB traces. Long-term reliability testing shows no parameter shift after 1000 hours at 85°C/85% RH, confirming AOZ8318DI's suitability for humid industrial enclosures and outdoor display housings.

Is the thermal pad on the AOZ8318DI internally connected, and how should it be handled in PCB layout?

Yes, the exposed thermal pad (pins 9–10) on the AOZ8318DI is internally connected to GND. It must be soldered to a solid copper ground plane on the PCB using at least nine 0.3mm-diameter thermal vias spaced evenly beneath the pad. Failure to connect the pad degrades ESD energy dissipation and raises clamping voltage by up to 2.5V under 12A pulses. Proper grounding also improves thermal stability during repeated discharges-critical for AOZ8318DI's sustained performance in high-use interfaces.