The 1.5SMC440AHE3_A/H: This is a unidirectional device (one channel) intended for DC rail protection where the signal stays above ground.
AEC-Q101 qualification and automotive deployment
The series carries AEC-Q101 qualification, the automotive-grade discrete semiconductor standard covering temperature cycling, humidity bias, and ESD robustness. This certification is required for Tier-1 and OEM PPAP submissions on engine control units, transmission modules, and body electronics where a TVS diode protects 24V or 48V bus lines from load-dump and inductive-kick transients. The DO-214AB (SMC) package footprint is shared with the broader 1.5SMC family — the same copper pad area under the cathode tab sets the thermal resistance to ambient. No power line protection feature is implemented; this is a standard TVS diode without integrated filtering.
Vishay has marked the 1.5SMC440AHE3_A/H as obsolete. The base product number 1.5SMC440 indicates the family; a pin-compatible alternative within the same 1.5SMC series may exist with a different suffix (e.g., non-automotive grade or different packaging). The AEC-Q101 qualification and the 'HE3' suffix (automotive-grade) are the distinguishing features that may not carry over to a commercial-grade substitute.