The STMicroelectronics X0202MN 5BA4 is a sensitive-gate SCR (silicon-controlled rectifier) rated for 600 V off-state blocking and 1.25 A RMS on-state current in a SOT-223 surface-mount package. The 200 µA maximum gate trigger current classifies it as a sensitive-gate device — compatible with low-current drive from logic-level outputs or MCU GPIO pins without an intermediate driver stage.
With a 600 V off-state voltage rating, this SCR can block the peak of a 277 VAC line (rectified to ~390 VDC) with margin — suitable for AC mains-rectified circuits or DC bus rails up to that voltage. The 1.25 A RMS on-state current defines the continuous load ceiling; for a resistive load like a heater or incandescent lamp, the average current (800 mA) is the thermal design limit, while the RMS rating governs the I²R heating in the die and package. The 5 mA maximum hold current means the SCR stays latched once triggered as long as the load current stays above that threshold — below 5 mA the device will commutate off, which matters for lightly loaded or pulsed circuits. Surge capability is specified at 22.5 A for 50 Hz and 25 A for 60 Hz half-cycle non-repetitive — this covers inrush from capacitive loads or lamp cold-filament surges without damaging the junction.
ROHS3 compliant, meeting the current EU RoHS exemption scope without reliance on expired exemptions — no lead, mercury, cadmium, or restricted phthalates above the threshold. Operating temperature range from -40°C to 125°C covers industrial and automotive interior environments — the junction temperature must stay within this window for the full rated blocking and conduction capability.