3750Vrms isolation in a compact 4-SOP
The Vishay SFH690CT is a single-channel optocoupler with a phototransistor output, designed for signal isolation in industrial and power-management circuits. Its 3750Vrms isolation rating suits it for breaking ground loops and providing safety isolation in AC mains or DC bus monitoring applications. The device comes in a 4-SMD gull-wing package (4-SOP with 2.54mm pin pitch), surface-mount ready for automated assembly.
CTR range and drive margin
The current transfer ratio is specified at 100% minimum and 200% maximum, both measured at a forward current of 5mA. This 2:1 spread is typical for transistor-output optocouplers and means the designer must ensure the receiving logic or load sees a valid signal across the full CTR range. A 1.15V typical forward voltage at the same 5mA drive helps keep the LED power budget predictable.
Switching speed and output ratings
Rise and fall times are 3µs and 4µs typical, with turn-on and turn-off times of 5µs and 3µs respectively. This places the SFH690CT in the general-purpose isolation class — adequate for 50/60 Hz line monitoring, relay drivers, and low-speed digital isolation, but not for high-speed data links. The output transistor is rated for 70V maximum and 50mA continuous current, with a saturation voltage of 300mV maximum at rated drive.
Temperature range and environment
The maximum DC forward current is 50mA, so the LED drive should be kept well below that for reliable long-term operation.
Lifecycle and compliance
No last-time-buy or obsolescence risk is indicated.