Clamping performance and pulse current capability
The 1.5SMC20CAHM6G: With a breakdown voltage minimum of 19V and a clamping voltage of 27.7V at 56A peak pulse current, the device absorbs transients that would otherwise exceed the absolute-maximum ratings of downstream ICs. The 56A figure is the peak current the diode can handle in the 10/1000µs pulse shape before the junction temperature hits the limit. The DO-214AB (SMC) package is a standard surface-mount footprint for 1500W-class TVS diodes — the large copper tab on the bottom side conducts heat into the PCB pad, so the board's copper area directly sets the derating for repetitive pulses.