800 V / 8 A Snubberless triac for AC power control
The STMicroelectronics T835T-8I is an 8 A Snubberless™ Alternistor triac in a TO-220AB insulated package, rated for 800 V off-state voltage.
Gate drive and triggering
Maximum gate trigger current is 35 mA, with a maximum gate trigger voltage of 1.3 V. That Igt is low enough to be driven directly by an optocoupler output or a small-signal transistor, but high enough to reject noise on long sense lines. The 40 mA holding current ensures the triac latches on once triggered and stays on through the AC zero-cross unless commutated.
Surge capability and thermal margin
Non-repetitive surge current is 60 A at 50 Hz and 63 A at 60 Hz — this covers inrush from incandescent lamps, capacitive loads, or motor start.
Through-hole TO-220-3 with an insulated tab (TO-220AB Insulated). The insulated backside means no mica washer or thermal pad is needed when bolting to a grounded heatsink — the package itself provides the isolation. The three leads are standard in-line; the tab is the main thermal path, so a dab of thermal compound and a snug screw torque matter more than the lead solder joints for current above a few amps.
ROHS3 compliant, so it ships without any of the six restricted substances plus the four phthalates. The Snubberless™ series is a standard ST power line, so second-source options exist (e.g., the T1235T-8FP at 12 A) but the T835T-8I itself is current and available through independent distribution. Quoted to order against BOM quantities.