What this SCR is and where it fits
The STMicroelectronics X0115ML is a sensitive-gate SCR thyristor rated for 600 V off-state blocking and 800 mA RMS on-state current. The sensitive gate (150 µA max gate trigger current) lets a microcontroller output or optocoupler drive it directly — no driver transistor needed, which shrinks the BOM on low-power phase-control or AC switching boards. Packaged in a SOT-23-3 surface-mount case, it fits compact designs where board space is tight. The -40°C to 125°C junction temperature range covers industrial enclosures, outdoor telecom, and under-hood automotive environments.
Key ratings and what they mean for your BOM
The 600 V off-state voltage provides margin for 120V AC and 240V AC line switching. The 500 mA average on-state current (800 mA RMS) handles small loads: relays, solenoids, indicator lamps, valve coils.
Package and storage
The X0115ML comes in a SOT-23-3 package (also known as TO-236-3 or SC-59). It is supplied on Tape & Reel (TR) or Cut Tape (CT) — standard for SMT pick-and-place. Store the reels in a dry cabinet or with desiccant; the small body is not moisture-sensitive by default, but keeping the reel sealed avoids any reflow issues.