A transistor can remain within a headline current rating yet be unsuitable for a particular voltage, current and duration together. This matters when an output spends time partly switched on.

Interpreting the evidence

Compare the actual operating event with the device’s safe operating area and thermal conditions. Investigate why the circuit enters that condition, including driver weakness or an abnormal load. Simply selecting a device with a larger advertised current rating can miss the failure mechanism.

Keep this evidence

Provide the load, failure timing and any waveform or thermal evidence from the original assessment.

Ratings are conditional. They must be read with the data sheet’s temperature and pulse-duration assumptions rather than treated as independent limits.

Speak to AXION

For ECU testing and component-level repair, send your vehicle details and fault report. Workshop assessment is in Didcot, Oxfordshire. Suitable postal or remote work is confirmed before booking.

Technical background from Nexperia. The referenced design explains the principle; the vehicle-specific procedure determines the repair.

Related reading — Repeated avalanche stress in an inductive output stage. Browse all vehicle-electronics diagnostic notes or return to the repair library.