1.2 kV blocking voltage, 25 A RMS — high-line industrial AC switching
The STMicroelectronics T2550-12T is a Snubberless™ alternistor triac rated for 1.2 kV off-state voltage and 25 A RMS on-state current in a TO-220-3 through-hole package. Designed for high-line AC switching in industrial heaters, motor drives, and power supplies where snubber circuits are undesirable, the Snubberless™ construction provides commutating dV/dt immunity without external RC networks. Single-device configuration with a 50 mA maximum gate trigger current and 1.3 V maximum gate trigger voltage keeps the drive circuit simple — a standard microcontroller I/O through a resistor can fire it.
Surge handling and inductive loads
Non-repetitive surge current is rated 240 A at 50 Hz and 252 A at 60 Hz, which covers the inrush from large motor starts or transformer energisation. The 60 mA maximum hold current means the triac stays latched through the zero-cross of an inductive load without premature dropout — a key spec for motor or solenoid control where the current waveform lags voltage.
For a BOM line needing 1.2 kV blocking voltage in a TO-220 footprint, this is a current-production choice with no LTB risk.