Sensitive-gate SCR for low-drive applications
The STMicroelectronics X0115MUF is a sensitive-gate SCR rated for 1 A RMS on-state current and 600 V off-state blocking, housed in a 3-SMB flat-lead surface-mount package (SMBflat-3L). The 150 µA maximum gate trigger current (Igt) means a low-current signal — from a microcontroller GPIO, a comparator output, or a Hall-effect sensor — can fire the SCR directly without a driver transistor or buffer stage. This simplifies the BOM and saves board area in applications like relay coil latching, small solenoid drivers, fan speed controls, and capacitive discharge ignition circuits where the control signal is current-limited.
1 A RMS / 600 V — sizing the load and the isolation
The 1 A RMS on-state current (It(RMS)) and 640 mA average (It(AV)) define the continuous load this SCR can handle. For a resistive load like a heater or incandescent lamp, the 1 A RMS rating gives headroom for inrush at turn-on. The 600 V off-state voltage (Vdrm/Vrrm) means it blocks mains peaks cleanly in 120 VAC or 277 VAC systems, and with margin for 240 VAC line transients. The 1.4 V maximum on-state voltage (Vtm) at rated current is typical for a 1 A SCR — the conduction loss is about 1.4 W at full load, so the SMBflat-3L package's thermal path to the PCB copper matters for continuous duty above 500 mA.
Active lifecycle, no obsolescence clock
ROHS3 compliance is confirmed.
Package and footprint — SMBflat-3L
The 3-SMB flat-lead package (SMBflat-3L) is a low-profile surface-mount alternative to through-hole SCRs in TO-92 or DPAK. The flat leads sit flush with the PCB, which helps with automated optical inspection and reduces tombstoning risk during reflow.