For which automotive applications is the SM8S series TVS suitable?

The SM8S series TVS is suitable for applications such as automotive power input protection, load dump protection, inductive load transient protection, power line surge protection, and high-energy transient protection. When selecting the SM8S series for automotive applications, key parameters to consider include operating voltage, clamping voltage, peak power, test waveforms, and package thermal dissipation conditions.

I. Suitable Automotive Locations for the SM8S

In automotive systems, components such as power inputs, 12V/24V power lines, central control units, cameras, T-BOXes, gateways, controllers, and motor-related modules may be exposed to high-energy transients.

The SM8S series is typically used for power-line protection scenarios that are more demanding than those suited for standard, small-package TVS diodes; it is not intended to replace low-capacitance ESD devices for high-speed signal lines.

II. Automotive Transient Characteristics

The automotive power supply environment is subject to battery voltage fluctuations, load dump events, relay switching, motor kickback, and wire harness coupling interference. These transients involve high energy and long durations, placing greater demands on the power handling and thermal capabilities of TVS devices.

Therefore, automotive power supply protection cannot rely solely on nominal voltage ratings; it must also take into account relevant testing standards and the operating voltage range of the entire system.

III. Key Selection Considerations

The VRWM must cover the maximum normal operating voltage, the VC must be lower than the withstand capability of downstream components, the peak power rating must meet the requirements of the test waveform, and the package's thermal dissipation must be suitable for the installation environment.

If the product must comply with automotive standards or higher reliability requirements, component selection should be based on a combination of customer test conditions, specifications, and certification requirements.

IV. Asym Solutions

Asym offers TVS, ESD, and EMI component solutions for automotive power supplies, CAN interfaces, cameras, central control units, and controllers; furthermore, the company leverages its expertise in EMC testing and remediation to assist customers in completing validation.

FAQs

Q: Can the SM8S be used for high-speed signal lines?

A: No, it is not suitable. The SM8S is better suited for high-energy power supply transient protection; low-capacitance ESD devices should be selected for high-speed signal lines.

Q: Why are high-power TVS devices used for automotive power supplies?

A: Because automotive wiring harnesses and power supply environments can generate high-energy transients, requiring a greater power margin.

Q: Should the selection of the SM8S be based solely on whether the system is 12V or 24V?

A: No; factors such as maximum operating voltage, clamping voltage, test waveforms, and power ratings must also be considered.