TVS diode for 75V rail protection
The SMCJ75CA-13: Its 75V reverse standoff voltage (VRWM) means it sits across a 75V DC bus without conducting in normal operation — the leakage at that rail voltage is negligible. When a surge exceeds the 83.3V minimum breakdown voltage, the device clamps at 121V maximum, shunting up to 12.4A of peak pulse current to ground.
What the clamping voltage means for your protected circuit
The 121V maximum clamping voltage at 12.4A peak pulse current is the voltage the downstream components see during a surge event. A 75V-rated DC-DC converter or a 100V-rated MOSFET on the same rail must have an absolute maximum rating above 121V — otherwise the TVS clamps at a voltage that still exceeds the protected device's breakdown.
Bidirectional protection in one package
With a single bidirectional channel, the SMCJ75CA-13 replaces two back-to-back unidirectional TVS diodes on a symmetrical AC signal line or a bipolar DC bus.