The BTA06-800BWRG is an STMicroelectronics Snubberless™ Alternistor triac in a TO-220-3 through-hole package. It switches AC loads up to 6 A RMS with an 800 V off-state blocking voltage — the 800 V rating gives you a 2× margin above a 277 VAC line, absorbing line transients without avalanche failure. The Snubberless™ designation means the triac is designed to commutate inductive loads (motors, solenoids, transformers) without an external RC snubber network. The internal die structure handles the dV/dt stress at turn-off that would otherwise latch a standard triac into conduction. This saves two passives per phase and cuts board space. The 50 mA holding current means the triac drops out of conduction when the load current falls below 50 mA near the AC zero-cross, which is the normal commutation point for resistive and most inductive loads.
Surge capability and thermal limits
Non-repetitive surge current is 60 A at 50 Hz and 63 A at 60 Hz for one cycle — this covers motor start inrush, capacitive load charging, and brief fault events. The TO-220 package has a metal tab that connects to the MT2 terminal. In a typical PCB layout, the tab is soldered to a copper pad on the board or bolted to a heatsink. The thermal resistance junction-to-case is not listed here, but for a 6 A RMS load at 25°C ambient, a small clip-on heatsink keeps the junction below 100°C. For continuous operation above 4 A RMS, a heatsink is recommended.