1 kV blocking — the derating margin that matters
The TYN1012TRG is a standard-recovery SCR from STMicroelectronics with a 1 kV off-state blocking voltage — that is the rating that decides whether this part survives in a 400/480 VAC rectifier or PFC front-end. At 1 kV, you have the headroom to absorb mains transients without avalanche breakdown, which is the difference between a field-return and a one-time commission. The 12 A RMS on-state current (8 A average) sets the thermal design target: the TO-220 tab needs a heatsink rated for the junction-to-ambient thermal resistance at your peak load current and ambient temperature.
Gate trigger current is 5 mA max, and the gate trigger voltage is 1.3 V max — low enough to drive directly from a 5 V logic output or an optocoupler transistor without a separate driver stage. Holding current is 15 mA max, which means the SCR self-latches once triggered and stays on until the load current drops below that threshold. Off-state leakage is 5 µA max, negligible in any practical design. The non-repetitive surge rating of 140 A at 50 Hz / 145 A at 60 Hz covers capacitor-charging inrush or motor-start events — the SCR will survive a brief overcurrent that would crack a smaller die.
Package and temperature grade — through-hole for serviceability
Through-hole matters in designs where vibration, thermal cycling, or field-service rework makes surface-mount a reliability risk — the leads take the mechanical strain off the die attach. The ROHS3 compliance means no exemption-listed substances — clean for EU RoHS declarations.