Automotive-grade Transil for 48V–58V rail protection
The STMicroelectronics SM15T68AY is a unidirectional Zener TVS diode from the SM15TY TRANSIL™ series, rated for 1500W peak pulse power (1.5kW) over a 10/1000µs waveform. It is designed to clamp transients on automotive power rails, with a reverse standoff voltage of 58.1V and a minimum breakdown voltage of 64.6V, clamping at 121V under peak pulse current.
1500W peak pulse — sizing the protection margin
For a 58.1V standoff rail, this translates to a peak pulse current of 83A under the 8/20µs waveform — the more common automotive surge shape. The 121V clamping voltage at that current gives the designer a hard ceiling for downstream device stress. When sizing the TVS for a given transient, the key check is whether the energy in the pulse (V_clamp × I_pp × pulse width) stays within the device's rated peak power. For a 48V battery line or a 58V alternator output, the SM15T68AY provides a solid margin for load-dump and inductive kickback events.
AEC-Q101 and the 150°C junction limit
Surface-mount SMC package for automated assembly
The SM15T68AY is supplied in a SMC package, a standard surface-mount footprint for medium-power TVS diodes. The SMC body handles the 1500W pulse without requiring a heatsink.