600 W bidirectional TVS for 70 V rails
The STMicroelectronics SM6T82CAY is a bidirectional Zener transient-voltage-suppression diode from the automotive-grade TRANSIL™ SM6TY series. It clamps transients on a 70 V nominal rail, handling 600 W peak pulse power (10/1000 µs waveform) and clamping at 146 V maximum.
AEC-Q101 and the 150 °C junction
For a BOM line going into an ECU or a transmission controller, that temperature grade is the deciding factor over a commercial-grade TVS.
Peak pulse current and clamping
Rated at 27 A peak pulse current for the 8/20 µs waveform, the SM6T82CAY can handle short-circuit and load-dump events on a 70 V supply. The 146 V clamping voltage gives the downstream components a hard ceiling: any DC-DC converter or linear regulator rated for 150 V or more has margin. The bidirectional configuration means a single device protects both polarities, saving board space versus two unidirectional diodes.
DO-214AA (SMB) footprint
Housed in the DO-214AA (SMB) package, this part uses the standard SMB land pattern. The package is MSL 1 by default for most ST TRANSIL parts, so no pre-bake is needed before reflow. The SMB footprint is shared across the SM6TY series, so a last-minute change to a different standoff voltage (e.g., SM6T24CAY) requires no board respin.