The STMicroelectronics P0102DA 2AL3 is a sensitive-gate SCR (silicon-controlled rectifier) in the through-hole TO-92-3 package, rated for 400 V off-state voltage and 800 mA RMS on-state current. The 200 µA maximum gate trigger current (Igt) means a standard microcontroller GPIO pin, through a series resistor, can fire the SCR directly without a driver transistor — useful for low-side switched loads in appliance or lighting controls. Operating temperature spans -40°C to 125°C, covering industrial enclosures and outdoor equipment where ambient heat or cold-soak is a factor.
The TO-226-3 / TO-92-3 (TO-226AA) package is a standard 3-lead through-hole footprint with 2.54 mm pin pitch — the same layout used by legacy 2N series SCRs and transistors, so a board originally laid out for a TO-92 thyristor accepts this part without a PCB spin. Available in Tape & Box (TB) or Cut Tape (CT) — the TB option suits hand-insertion or low-volume assembly where reeled tape is unnecessary; CT works for prototype runs where partial reels are acceptable.
Surge and hold current behaviour
Non-repetitive surge current is 7 A at 50 Hz and 8 A at 60 Hz — this is the peak the die can survive for one cycle during capacitor inrush or lamp cold-start; the 800 mA RMS continuous rating is the steady-state limit, not the surge. Maximum holding current (Ih) is 5 mA — once triggered, the SCR latches until the load current drops below this threshold. In a DC circuit with a resistive load, the supply must be interrupted or the current forced below 5 mA to commutate the device off.
ROHS3 compliant per the manufacturer's declaration — no restricted substances above the threshold limits, which clears it for EU-market shipments and most global RoHS regimes without an exemption certificate.