TVS for automotive bus protection
It clamps transients at 69.7V maximum while carrying a 33.3V reverse standoff rating, making it a fit for 24V vehicle electrical systems or 28V nominal industrial rails.
Bidirectional — one device for symmetrical lines
With a single bidirectional channel, the SM6T39CAY protects signal pairs where polarity reverses or where AC coupling exists — CAN bus, LIN bus, or RS-485 transceiver lines. No need to series two unidirectional devices; one SMB footprint covers both positive and negative transients. The breakdown voltage starts at 37.1V minimum, so it stays clear of the 33.3V standoff under steady-state conditions.
The 150°C TJ ceiling gives margin for self-heating during repetitive surge events.
Housed in the DO-214AA (SMB) surface-mount package, the SM6T39CAY fits standard SMB footprints used across the SM6TY family. The SMB body is large enough to dissipate the 600W pulse without requiring a heatsink, but the PCB copper landing pads should follow the recommended pattern from the application note to keep thermal impedance low.