What this 20 A sensitive-gate SCR is for
The STMicroelectronics TN2010H-6T is a 600 V, 20 A RMS sensitive-gate SCR in a TO-220-3 through-hole package. The 10 mA maximum gate trigger current means a small-signal transistor, a logic output, or even a microcontroller GPIO with a series resistor can fire it directly — no separate driver transistor needed. That saves a couple of components and a bit of board area in phase-control circuits like dimmers, heater controls, and small motor speed controllers.
Gate trigger current — the sensitive-gate advantage
With a maximum gate trigger current of 10 mA and a maximum gate trigger voltage of 1.3 V, this SCR qualifies as a sensitive-gate device. That is the spec that matters if you are driving it from a microcontroller pin or an optocoupler output. A standard SCR might need 30 mA or 50 mA Igt, which forces a transistor buffer stage. Here, a 5 V logic signal through a 330 Ω resistor will usually fire it. The 5 µA maximum off-state leakage at 600 V means it stays off cleanly in high-impedance circuits.
The 20 A RMS on-state current is the continuous rating you use for thermal design. The 12.7 A average rating is the DC-equivalent value for half-wave or phase-angle applications. For inrush events — a motor start, a lamp cold filament, or a capacitor bank — the non-repetitive surge rating is 180 A at 60 Hz and 197 A at 50 Hz. That is a half-cycle sine wave, not a repetitive event. The 1.6 V maximum on-state voltage at peak current tells you the conduction loss: at 12.7 A average, expect roughly 20 W to dissipate through the TO-220 tab. The 40 mA maximum holding current means it will latch on with a moderate load and stay on until the current drops below that threshold — relevant for inductive loads where the current zero-crossing is the turn-off point.
The TO-220-3 through-hole package with a metal tab is the standard power package for this current class. The tab is the anode connection and needs electrical isolation if you bolt it to a grounded heatsink — use a sil-pad or mica washer. The through-hole leads handle the 20 A RMS with adequate trace cross-section on the PCB side.
No PCN or LTB date is associated with this part number.