Snubberless Alternistor for line-voltage loads
The STMicroelectronics T835H-6I is an 8 A RMS, 600 V off-state Snubberless Alternistor triac in a TO-220-3 through-hole package. The Snubberless construction means it commutates resistive and lightly inductive loads without an external RC snubber — the device handles the dV/dt turn-off stress internally. That saves two passives per triac on the BOM and frees board area in crowded power stages.
150°C junction — headroom for hot enclosures
The 150°C ceiling is useful in motor-drive cabinets, PFC stages near heatsinks, or outdoor lighting ballasts where still air and solar load push internal temperatures up. The 35 mA gate trigger current (Igt) and 35 mA holding current (Ih) are standard for this current class and are compatible with standard MCU GPIOs driving through a transistor or optocoupler.
Surge rating and inrush handling
Non-repetitive surge current is 80 A at 50 Hz and 84 A at 60 Hz (Itsm). The 60 Hz figure is the one to compare against the let-through of a fast-acting fuse or circuit breaker in a motor-start or lamp-inrush application. The 8 A RMS continuous rating assumes adequate heatsinking; the TO-220 tab is the thermal path — the junction-to-case thermal impedance sets the heatsink size.
The base product number is T835; the -6I suffix indicates the Snubberless grade and the TO-220 package variant.