Darlington gain at low drive current
The MOC223M is a single-channel Darlington-output optoisolator from onsemi in an 8-SOIC surface-mount package. Its headline spec is a minimum current transfer ratio of 500% at a forward current of only 1 mA — so a 1 mA LED drive can sink 5 mA or more on the output side, enough to drive a PLC input, a small relay coil, or a logic gate without an external buffer transistor. The Darlington with Base output gives the designer access to the base node for external pull-up or speed-up components, which can reduce the turn-off time below the typical 125 µs when the application needs faster recovery.
Isolation and temperature envelope for industrial I/O
Rated for 2500Vrms galvanic isolation, the MOC223M provides a basic safety barrier between the low-voltage control side and the higher-voltage load side — typical in 24 VDC industrial I/O modules, sensor interfaces, and motor drive feedback circuits. The operating temperature range of -40°C to 100°C covers factory-floor, outdoor telecom cabinets, and HVAC equipment, but does not extend to extended automotive under-hood or military environments. The 8-SOIC package (0.154" body width, 3.90 mm) is a standard surface-mount footprint shared by many optocouplers, making PCB layout straightforward with existing land patterns.
Active lifecycle and sourcing posture
ROHS3 compliant, with no exemption flags. For volume production, confirm the tube-to-reel conversion with your preferred distributor; reel quantities may be available under a different order code.
Switching speed and load drive
Typical rise time is 8 µs and fall time is 110 µs; turn-on is 10 µs, turn-off 125 µs. These figures suit low-frequency switching (relays, solenoid valves, indicator lamps) but are too slow for high-speed serial isolation or PWM above a few kilohertz. The output can sink up to 150 mA continuous at a maximum collector-emitter voltage of 30 V, with a saturation voltage of 1 V at rated current — adequate for driving a 24 V relay coil with a series resistor or a 5 V logic rail through a pull-up.