Automotive-grade transient suppression for 33V rails
The 1.5SMC39CAHM6G: It clamps transients at 53.9V maximum from a 33.3V reverse standoff voltage, with a minimum breakdown of 37.1V.
The 33.3V standoff is the maximum continuous DC voltage the part blocks without conducting; above that, breakdown starts at 37.1V minimum, and clamping is guaranteed at 53.9V. For a 24V automotive battery line that sees 36V during load-dump, this diode sits below the 36V rail and clamps the surge before it reaches downstream silicon.