8 A RMS sensitive-gate SCR in IPAK
The TS820-600H is an 8 A RMS (5 A average) sensitive-gate SCR from STMicroelectronics, rated for 600 V off-state blocking. The 200 µA max gate trigger current lets a low-power microcontroller GPIO or a simple transistor switch fire it directly — no separate driver stage needed for most loads. Housed in the IPAK (TO-251AA) through-hole package with short leads, it mounts into a compact footprint on the board and handles the thermal load of a 5 A average conduction without a heatsink in moderate ambient conditions.
Current, surge, and temperature envelope
Rated 8 A RMS continuous on-state current and 5 A average — the RMS figure governs the resistive heating in the die, so a 5 A DC load or an 8 A half-wave rectified load both stay within the SOA. Non-repetitive surge capability is 70 A at 50 Hz and 73 A at 60 Hz, covering inrush from capacitive or incandescent loads on power-up. Operating temperature spans -40°C to 125°C, which covers industrial enclosures and outdoor equipment. The 5 mA max holding current means the SCR latches reliably once triggered and does not drop out on light loads.
Gate drive and leakage
Gate trigger voltage is 800 mV max, compatible with 3.3 V logic levels through a current-limiting resistor. Off-state leakage is 5 µA max at rated voltage — negligible in most circuits, but worth noting if the load is a high-impedance sensor that sees the leakage as a bias current. On-state voltage drop is 1.6 V max at rated current — this sets the conduction loss. At 5 A average, dissipation is roughly 8 W; a small clip-on heatsink keeps the junction below 125°C in still air.