Load Dump TVS (DO-218)
Heavy-duty TVS purpose-built for automotive 12 V / 24 V load-dump surge events.
What is it?
A load dump occurs in vehicles when the battery is suddenly disconnected from the running alternator (loose battery cable, jump-starting). The alternator's stored magnetic energy then dumps into the 12 V or 24 V rail, producing a 40-100 V transient lasting 50-400 ms. Standard 8/20 μs TVS will fail this — the pulse is far too long. Load Dump TVS in DO-218AB package have huge die and explicit 10/1000 μs surge ratings to absorb the multi-joule load-dump energy.
When do you need it?
- Any automotive 12 V or 24 V power rail input on an ECU, infotainment unit, or accessory.
- ISO 7637-2 Pulse 5a (test pulse 5a, unsuppressed load dump) or 5b (suppressed) compliance.
- ISO 16750-2 protection requirements for automotive electronics.
- Heavy trucks and industrial vehicles with 24 V systems where transients reach 200 V+.
- Power-input modules for off-road / marine / agricultural equipment.
How to pick the right one
- VRWM matched to rail
- Use 24-27 V VRWM for 12 V automotive rails (allows for 16 V jump-start headroom). Use 36-40 V VRWM for 24 V truck rails.
- VC at full IPP
- Check the 10/1000 μs clamping voltage, not just the 8/20 μs spec. Load dump is a long pulse — the device may clamp higher under the longer waveform.
- IPP at 10/1000 μs
- Standard 8/20 μs IPP is misleading for load dump. The 10/1000 μs IPP rating is the one that matters. DO-218AB parts give 30-100 A at 10/1000.
- Power dissipation
- Load dump energy can be 5-10 J. Check the device can absorb that without thermal failure.
- AEC-Q101 qualification
- Mandatory for automotive use. Magnias DO-218AB load-dump parts are AEC-Q101 qualified.
What Magnias offers
Magnias offers a full DO-218AB load-dump TVS family covering 12 V and 24 V automotive rails, with explicit 10/1000 μs ratings and AEC-Q101 qualification. Our parts pass ISO 7637-2 Pulse 5b and ISO 16750-2 with margin. For applications also seeing IEC 61000-4-5 lightning surge, we recommend pairing one of our standard 8/20 μs TVS in parallel with the load-dump TVS — let the fast TVS clamp the lightning, let the load-dump TVS absorb the long pulse.