Transient protection for automotive 12V and 24V rails
The 1.5SMC20CAHE3_A/I: Its 17.1V reverse standoff voltage and 27.7V clamping point make it a fit for protecting 12V and 24V automotive power buses, sensor lines, and communication interfaces against load-dump and inductive-switching transients. AEC-Q101 qualification and the -65°C to 150°C junction temperature range confirm the part is screened for automotive-grade reliability — the temperature margin covers under-hood ambient plus self-heating during a pulse event.
What the clamping envelope means for circuit protection
At the 17.1V reverse standoff voltage, the diode draws negligible leakage current and does not interfere with the normal rail voltage. When a transient exceeds the 19V minimum breakdown, the Zener junction avalanches and clamps the line to 27.7V maximum while shunting up to 54.2A of peak pulse current.
Package and board integration
Housed in the DO-214AB (SMC) package, also designated as SMCJ, this is a standard surface-mount footprint for 1500W TVS diodes. The package's large copper tab on the cathode side (for unidirectional variants) or the body itself (for bidirectional) conducts heat into the PCB copper plane — the 1500W rating assumes a low-thermal-resistance board layout with adequate pad area and vias to the inner layers. Tape & Reel packaging supports automated pick-and-place assembly. The base product number 1.5SMC20 identifies the voltage family; the suffix CA indicates bidirectional, HE3 the automotive-grade AEC-Q101 screening, and _A/I the lead-free / RoHS-compliant termination finish.