25 A RMS SCR in a TO-220 — the workhorse phase-control thyristor
The ST TYN625RG is a standard-recovery SCR in a TO-220-3 through-hole package, rated to block 600 V off-state and conduct 25 A RMS on-state continuous. That 25 A RMS figure is the thermal limit in a typical 50/60 Hz phase-control circuit — the average current rating of 16 A tells you the DC-load ceiling if you're rectifying rather than phase-firing. The 300 A / 314 A non-repetitive surge rating covers the inrush from a motor start or capacitor bank charging without the die fracturing.
Gate trigger current (Igt) is 40 mA max and gate trigger voltage (Vgt) is 1.3 V max. Holding current (Ih) is 50 mA max — once triggered, the SCR latches until the load current drops below that threshold.
Package and mounting — TO-220 with a heatsink tab
The TO-220-3 package with through-hole mounting is the standard three-lead power package. The metal tab is the anode connection and the primary thermal path — it must be electrically isolated from the heatsink or connected to the circuit common, depending on the topology. The tube shipment is typical for through-hole power devices; the tube protects the leads during handling.