Dual Darlington opto — 500% CTR at 1 mA forward
The MOCD223VM is a two-channel Darlington-output optoisolator from onsemi in an 8-SOIC narrow-body package. The Darlington pair on the output side delivers a minimum current transfer ratio of 500% at just 1 mA LED forward current — so a 1 mA input can switch up to 150 mA per channel on the output side, enough to drive a small relay, a solenoid valve, or a PLC digital input module directly without a buffer transistor. Isolation is rated at 2500 Vrms, which covers functional isolation in 24 VDC control circuits, sensor interfaces, and general-purpose signal isolation where reinforced or double insulation is not required. The 8 µs rise and 110 µs fall times (10 µs turn-on, 125 µs turn-off) mean this part is suited for DC-level switching and low-frequency signals — not for high-speed data or PWM above a few hundred hertz.
ROHS3 compliance means no restricted-substance exemptions that could expire mid-production. The part ships in tube packaging, so it is compatible with standard tube-fed pick-and-place equipment; no reel or tape-and-reel handling required for prototyping or low-volume builds.
Output drive and temperature envelope
Each Darlington channel can sink up to 150 mA continuous at a maximum output voltage of 30 V, with a Vce saturation of 1 V at rated current — the 1 V drop at 150 mA means about 150 mW dissipation per channel, well within the SOIC package's thermal budget at 25°C ambient. Maximum forward current on the LED side is 60 mA, with a typical forward voltage of 1.25 V at rated drive. The 500% minimum CTR at 1 mA means the designer can run the LED at 1-5 mA and still get reliable logic-level switching on the output — useful for battery-powered or power-budgeted I/O isolation.