TVS diode for 75 V rail protection
The SMCJ75A-13: Its 83.3 V minimum breakdown voltage means it stays out of circuit during normal operation, but when a surge hits, it clamps at 121 V max while handling a 12.4 A peak pulse current (10/1000 µs waveform). That 121 V clamp ceiling is what the downstream silicon sees — if your 75 V bus feeds a converter with a 130 V abs-max input, this TVS buys you margin. The -55°C to 150°C junction temperature range covers the full industrial and automotive ambient envelope. The 1500 W rating is derated above 25°C per the standard TVS derating curve — at 125°C ambient, the peak pulse power drops to roughly 750 W, so the actual surge capability at temperature is half the headline figure.
DO-214AB (SMC) package and rework
The DO-214AB (SMC) package is a standard JEDEC footprint with a large copper tab on the cathode side. The tab carries the heat and the current — the board-side pad should have thermal vias to a copper plane to keep the junction temperature under 150°C during repetitive surges. Under the hot-air station, the SMC body takes about 10 seconds at 350°C to reflow; the tab wets quickly if the pad has enough solder paste. Pin 1 is the cathode band — the band is moulded into the body, not just printed, so it survives a rework cycle without fading. The package is rated for surface-mount assembly with standard lead-free profiles.