28.2V standoff, 600W peak pulse — automotive-grade TVS in SMB
The P6SMB33AT3 from onsemi is a single-direction Zener TVS diode rated at 28.2V reverse standoff voltage with a minimum breakdown of 31.4V. It clamps transients to 45.7V maximum at 13.2A peak pulse current (10/1000µs waveform), delivering 600W peak pulse power.
For a 24V nominal supply (e.g., truck or industrial bus), this clamp is well above the rail, so the downstream DC/DC or load switch must survive that transient. The 585pF typical capacitance at 1MHz is moderate — fine for DC power lines but may load high-speed signal lines; for data interfaces, consider a lower-capacitance TVS. The 13.2A peak pulse current rating at 10/1000µs defines the surge withstand. In a 24V system with a 2-ohm source impedance, a 100V transient would push about 36A — this part would clamp but exceed its rating, so a higher-power TVS or series resistor may be needed. The 600W peak pulse power is the product of clamp voltage and current; derate for higher ambient temperature per the datasheet curve.