5000 Vrms isolation — the safety barrier spec
The VOL617A-7X001T is a single-channel phototransistor optocoupler from Vishay, with a 5000 Vrms isolation rating that sets the reinforced insulation barrier between the DC input and the transistor output. That 5 kV rating is the figure that drives creepage and clearance on the PCB — the 4-SMD gull wing package (4-SOP) keeps the input-to-output spacing tight enough for a 2-layer board but wide enough to pass IEC 60950-1 reinforced insulation for 250 V working voltage.
CTR 80%–160% at 5 mA — gain margin for logic interfaces
Current transfer ratio is the gain from LED forward current to collector current. The VOL617A-7X001T guarantees 80% minimum and 160% maximum CTR at If=5 mA — that 2:1 spread means the output transistor can saturate a 5 V CMOS logic input with as little as 1.6 mA of collector drive, leaving margin for LED ageing and temperature drift. The typical Vce saturation of 400 mV ensures the output pulls low enough to register a solid logic 0.
Vishay has not issued a PCN or end-of-life notice for this order code.
The 110°C ceiling is 15°C above the typical 85°C industrial limit, which gives thermal margin in a sealed enclosure. The 3.5 µs rise and 5 µs fall times are adequate for 10 kHz switching or digital signal isolation; for faster edges, a logic-output optocoupler would be a better fit.