Single-channel transistor-output optocoupler with 3750Vrms isolation
The Vishay VOS615A-2X001T is a single-channel optocoupler with a phototransistor output, housed in a compact 4-SSOP surface-mount package. It provides 3750Vrms galvanic isolation between a DC input LED and a 80V-rated transistor output, making it a fit for signal isolation in industrial controls, PLC digital inputs, motor-drive feedback paths, and isolated power-supply error amplifiers.
The current transfer ratio spans 63% to 125% at a 10 mA forward current. That 63% floor is the number to budget for — it ensures the output transistor can saturate into a logic input or a 50 mA load even with LED ageing and temperature drift across the -55°C to 110°C range. The 400mV Vce saturation maximum at that CTR corner keeps the logic-low voltage well within a 5V or 3.3V receiver threshold.
Switching speed and drive timing
That puts this part in the medium-speed class — fine for 10 kHz to maybe 50 kHz switching in a PSU feedback loop or a 9600 baud serial isolator, but not for high-speed digital isolation above a few hundred kHz. The 1.2V typical forward voltage means a 3.3V or 5V logic output can drive the LED directly through a current-limiting resistor.
The 4-SSOP body (0.173" wide, 4.40mm) is a small-outline gull-wing package. It reworks well with hot air at 300°C for 10 seconds; the leads are visible enough to inspect solder joints. No exposed pad means no thermal-via stitching needed.