3 kW TVS clamp for 16 V automotive buses
The STMicroelectronics SM30T19CAY is a bidirectional Zener-type transient voltage suppressor from the TRANSIL family, designed to protect sensitive electronics on 16 V nominal supply rails from surges up to 3 kW peak pulse power per the 10/1000 µs waveform. It clamps a 115.4 A peak pulse current to 26 V maximum, which keeps the voltage stress on downstream components like ECUs, sensors, or communication transceivers within their safe operating area during load-dump or ISO 7637 transients.
Peak pulse power and clamping — the protection envelope
At 3 kW peak pulse power, this part absorbs substantial surge energy before the clamping action limits the voltage. The 26 V clamp at 115.4 A defines the worst-case transient the protected circuit sees — the key figure for confirming headroom against the absolute maximum ratings of the ICs on that rail. With a 16 V reverse standoff voltage, the SM30T19CAY is intended for continuous DC bus voltages up to 16 V; it remains high-impedance below that threshold and only starts conducting significantly above the 17.8 V minimum breakdown voltage.
Package and mounting — SMC footprint for power dissipation
Housed in the DO-214AB (SMC) surface-mount package, the SM30T19CAY provides a larger copper pad area under the cathode tab compared to smaller SMA/SMB packages, which lowers the thermal resistance to the PCB and supports the 3 kW surge rating without exceeding the junction temperature limit. No power line protection feature is built in — this is a transient clamp, not a regulator.
Lifecycle and sourcing status
This makes it suitable for new design-in as well as sustained production runs. No official second-source or pin-compatible cross-reference is listed in the ledger, so dual-sourcing evaluation would require testing an alternative from the same TRANSIL series or a competitive automotive TVS family.