Automotive TVS Applications: Protecting ECUs, Power Rails and Vehicle Networks

An automotive TVS diode is used wherever a vehicle cable can carry a damaging transient into an electronic module. The application determines the device: a high-energy battery input, a motor driver, a CAN transceiver and a camera link do not need the same TVS.

This guide maps common automotive TVS applications to the protection point, electrical threat and practical selection priority.

1. ECU Battery Input and Load-Dump Protection

Engine controllers, body control modules, domain controllers and aftermarket modules connect to long battery wiring. They can experience load dump, jump-start conditions, inductive switching and negative pulses.

A typical protected input is:

Connector → fuse or current limiting → reverse-battery protection → TVS → input filter → DC-DC converter

Place the TVS near the power entry so surge current does not cross the sensitive ground area. Select its reverse standoff voltage above the highest valid operating voltage, then confirm that its clamping voltage remains below the downstream converter limit at the required pulse current. An unsuppressed load-dump test may require a much larger device than a centrally suppressed vehicle architecture.

2. Motors, Relays and Solenoid Loads

Door locks, seats, wipers, pumps, fans and valves generate inductive voltage when current is interrupted. A local TVS across the load, driver output or protected supply can limit the spike and reduce stress on MOSFETs and control ICs.

The best location depends on the required release speed and current path. A simple flyback diode produces slow current decay; a higher-voltage TVS clamp can release a relay or solenoid faster. Verify repetitive pulse heating because these events may occur thousands of times during vehicle life.

3. CAN, CAN FD and LIN Interfaces

Vehicle networks run through the wiring harness and exit each ECU at a connector. They need local protection against ESD, coupled transients and harness disturbances.

• CAN/CAN FD: use a low-capacitance, bidirectional two-line device compatible with the transceiver's common-mode range and data rate.
• LIN: protect the single bus line without excessive leakage or capacitance.
• Placement: install the TVS on the connector side of the transceiver with short, balanced routing.

YINT's automotive device selection guide provides application references for LIN, CAN, CAN FD and automotive Ethernet interfaces.

4. ADAS Cameras, Displays and High-Speed Links

Front cameras, surround-view modules, digital mirrors, displays and infotainment systems use LVDS, automotive Ethernet, USB or other high-speed interfaces. Here, signal integrity is often the limiting factor.

Use ultra-low-capacitance ESD/TVS arrays and a flow-through package where possible. Protect each exposed connector locally, keep differential traces symmetrical and minimize stubs. A large power TVS placed on a high-speed pair may stop ESD but also close the eye diagram.

YINT's automotive display protection solution shows coordinated protection for display power and signal ports.

5. 24V and 48V Vehicle Systems

Trucks, construction equipment, 48V subsystems and electrified vehicles operate at higher normal voltage and may store more surge energy. Do not scale a 12V design by voltage alone. Recalculate the valid operating range, source impedance, pulse energy, temperature derating and downstream absolute maximum rating.

On-board chargers, battery-management modules and 48V distribution units may also require coordinated fuses, current limiting, reverse-polarity protection and isolation. A TVS handles transient energy; it is not a substitute for continuous overvoltage protection.

Application-Based Selection Checklist

1. Identify the exact connector pin and protected circuit.
2. Record maximum normal voltage, including charging and jump-start conditions.
3. Define the ISO or OEM pulse waveform, source impedance and repetition count.
4. Choose power capability for supply lines or low capacitance for data lines.
5. Check clamping voltage at the real current and worst temperature.
6. Measure residual voltage at the IC during system testing.

Common Automotive TVS Mistakes

• Selecting from nominal battery voltage only
• Treating AEC-Q101 qualification as proof of load-dump compliance
• Using one central TVS but leaving exposed signal ports unprotected
• Ignoring PCB and harness inductance when estimating peak voltage
• Comparing peak power ratings with different pulse waveforms

Contact YINT Electronics

YINT Electronics supplies automotive TVS diodes and interface-protection solutions. For help matching a device to an ECU, motor, network or high-speed link, contact global@yint.com.cn.