1500 W bidirectional TVS — clamping and standoff for a 24 V rail
The 1.5SMC22CA-M3/57T: Its 18.8 V reverse standoff voltage and 30.6 V clamping point make it a fit for protecting 24 V DC buses and unipolar signal lines where the normal operating voltage stays below 18.8 V. The bidirectional channel means a single device clamps both polarities, saving board space over back-to-back unidirectional parts.
Breakdown and clamping — what the numbers mean for the rail
Minimum breakdown voltage is 20.9 V, so the device starts conducting above that level. The 18.8 V reverse standoff is the maximum DC or peak AC voltage the TVS can sit across without significant leakage — a 24 V nominal rail with 5 % tolerance sits at 25.2 V, which exceeds this standoff, so this part suits a regulated 24 V bus with tight tolerance or a 12 V rail with margin. Clamping at 30.6 V means the protected circuit sees no more than that during a surge event. For a downstream DC-DC converter with a 36 V abs-max input, this provides adequate headroom. The DO-214AB (SMC) package with surface-mount mounting suits reflow assembly and keeps the thermal path through the solder joint to the PCB copper.