The Vishay VO207AT is a single-channel optocoupler in an 8-SOIC package, built around a DC-input LED and a phototransistor with base access. Its 4000Vrms isolation rating makes it a candidate for breaking ground loops and providing basic insulation in industrial control interfaces, PLC digital inputs, and isolated sensor feedback paths. The base terminal is brought out, which lets the designer add a base-emitter resistor to tailor switching speed or suppress leakage at elevated temperature.
CTR window and output drive — sizing the LED current
The current transfer ratio is specified from 100% to 200% at a forward current of 10mA. That window means a 10mA LED drive yields 10mA to 20mA of collector current in the output transistor, enough to drive a logic input or a low-current relay coil directly. The output transistor is rated for 70V maximum and 50mA continuous per channel, with a maximum Vce(sat) of 400mV at the rated current — the drop is low enough to keep the output rail within a logic-high threshold when sinking a few milliamps.
Switching speed and temperature range
Typical rise and fall times are 3µs and 2µs respectively, with turn-on and turn-off times both at 3µs. That puts the VO207AT in the general-purpose speed class — fine for 10kHz to 50kHz switching or status feedback, but not for high-speed serial isolation.