The 6N139V: It uses a DC input LED driving a Darlington phototransistor output with a base connection, giving a minimum current transfer ratio of 500 % at a forward current of just 1.6 mA. Isolation is rated at 2500 Vrms, which covers basic functional isolation in industrial control, PLC I/O modules, and isolated data interfaces where the signal path needs to cross a safety barrier without galvanic continuity.
Switching speed and drive requirements
Typical turn-on time is 1.5 µs and turn-off time is 7 µs, placing this part in the medium-speed class for optoisolators. The Darlington output provides high gain — the 500 % minimum CTR means the output can sink 60 mA continuously from a 1.6 mA LED drive, which is useful for driving a logic gate input or a small relay directly without a buffer transistor.
Temperature range and package
The through-hole DIP package is suitable for prototyping, low-volume production, and applications where vibration is not a primary concern — the leads provide mechanical strain relief compared to surface-mount packages.
onsemi lists the 6N139V as Obsolete. No official successor or pin-compatible replacement is recorded in the available documentation.