Galvanic isolation for industrial logic interfaces
The onsemi 4N30M is a single-channel optoisolator that provides 4170 Vrms of galvanic isolation between a DC input and a Darlington with Base output. This isolation rating is specified per the device's 6-DIP package and is suitable for breaking ground loops and protecting low-voltage logic from transient voltages on the field side of industrial control interfaces. The Darlington with Base output configuration delivers a minimum current transfer ratio of 100% at an input forward current of 10 mA, meaning the output can sink at least as much current as the input drives. This high gain reduces the burden on the upstream logic driver and provides margin for LED degradation over temperature and time.
Switching speed and output drive capability
Turn-on time is 5 µs typical, while turn-off time extends to 40 µs maximum. This asymmetric switching characteristic is typical of Darlington output stages and sets the upper limit for data rate — the part is suited for DC-level sensing, relay replacement, and low-frequency signal isolation rather than high-speed digital communication. The output can sink up to 150 mA continuously at a maximum collector-emitter voltage of 30 V, with a saturation voltage of 1 V at rated current. This drive capability is sufficient to energise a small relay coil, a PLC input module, or a logic-level load directly without an external transistor buffer.
Through-hole DIP package and board integration
The 2.54 mm pin pitch is compatible with standard prototyping boards and existing DIP footprints used in legacy industrial designs. The tube packaging is the standard delivery format for through-hole DIPs; parts are shipped in antistatic tubes suitable for automated insertion or manual assembly.