Surge rating and the clamping decision
The 1.5SMC20CA R7G: The 17.1V reverse standoff is the maximum continuous DC voltage the TVS can block without conducting leakage. The 19V minimum breakdown voltage sets the guard band — a 17.1V rail with 5% regulation rides at 16.2V, leaving nearly 3V of margin before the TVS starts clamping.
Package and thermal footprint
One channel, one placement on the board, one BOM line for both polarities.
Lifecycle and procurement posture
The 1.5SMC series is a mature, widely second-sourced platform; the DO-214AB package and 1500W rating are industry-standard, so alternate sources exist if supply tightens.