Sensitive gate SCR for low-power trigger circuits
The STMicroelectronics X0202NA 1BA2 is a sensitive gate silicon controlled rectifier (SCR) in a TO-92-3 through-hole package, designed for applications where the gate drive comes from a low-current source such as a microcontroller I/O pin, a Hall-effect sensor, or a comparator output. Its defining characteristic is the 200 µA maximum gate trigger current (Igt) and 800 mV maximum gate trigger voltage (Vgt), which classify it as a sensitive gate device — meaning it can be switched on directly without a separate driver transistor, saving board space and BOM cost in low-power phase-control and switching circuits.
800 V blocking and 1.25 A continuous rating
With an 800 V off-state voltage rating, the X0202NA 1BA2 is suited for 120 VAC and 240 VAC line-powered designs where the SCR must block the full rectified peak. The 1.25 A RMS on-state current (800 mA average) defines the continuous load it can handle in a TO-92 package — typical loads include small solenoids, incandescent lamps, resistive heaters, and low-power universal motors. The 22.5 A / 25 A non-repetitive surge current rating (50/60 Hz) gives headroom for capacitive inrush or short-duration fault events without immediate failure.
Active lifecycle and ROHS3 compliance
For dual-source planning, the closest functional peer in the same sensitive-gate, TO-92 family is the X00602MA 1AA2, which is rated at 600 V off-state — a drop of 200 V from this part. If your design requires the full 800 V blocking, the X0202NA 1BA2 is the correct choice; the 600 V variant is a cost-reduction option only if the application's peak voltage stays below 600 V.