The 1.5SMBJ16A: The standard SMB footprint with a 0.200-inch (5.08 mm) pad pitch on the cathode side handles the 1500W peak pulse without lifting the pad during a surge event — the copper pad area under the tab sets the thermal impedance for the transient, not the steady-state dissipation.
The 57.7A peak pulse current at the 26V clamping voltage means a 16V nominal rail can ride through a 57.7A surge before the clamp forces the voltage to 26V, protecting downstream silicon rated at 30V abs-max. The reverse standoff voltage is 16V, breakdown minimum is 17.8V, and maximum clamping is 26V at Ipp. For a 12V automotive battery line (nominal 13.8V, transient to 16V), this part starts conducting at 17.8V — it stays off during normal operation and only clamps during a load-dump or inductive kick. The single unidirectional channel means the cathode goes to the protected rail and the anode to ground; reverse-polarity events forward-bias the junction and the part conducts as a Schottky until the fuse opens.
Automotive grade and operating envelope
The 1.5SMBJ series is the standard 1500W SMB TVS family from Bourns; the 1.5SMBJ16A is the 16V standoff variant.