Single-channel 5300Vrms optocoupler for isolated feedback and signal transfer
The Vishay SFH6186-5X001T is a single-channel DC-input phototransistor optocoupler in a 4-SMD gull-wing package, rated for 5300Vrms isolation. It delivers a current transfer ratio of 250% to 500% at 1 mA forward current, making it suitable for applications where the LED drive current is limited and a high CTR margin is needed to guarantee the output saturates over temperature and lifetime. The transistor output can sink up to 50 mA and withstand 55 V on the collector, which covers driving a logic input, a small relay, or a low-side switch in isolated power-supply feedback loops, motor-drive status signals, and industrial PLC I/O modules.
CTR spread and bias design
The 250% minimum CTR at 1 mA forward current is the number to design around. The wide CTR range (250% to 500%) means the load resistor on the output side must be chosen so that even at the minimum CTR the output transistor saturates — the 400 mV Vce(sat) maximum gives a clean logic low. At the maximum CTR, the same resistor will still be within the output current rating of 50 mA, so no overdrive concern.
Rise and fall times are 3.5 µs and 5 µs typical, with turn-on and turn-off times of 6 µs and 5.5 µs. That places the usable data rate around 50 kbps or slower — fine for 50/60 Hz zero-crossing detection, relay-coil feedback, or slow GPIO isolation, but not for high-speed digital buses like SPI or I²C. The DC input type means the LED is simply on or off; no AC coupling or carrier modulation is needed.
The ROHS3 compliance simplifies EU and global compliance paperwork.
That means no last-time-buy pressure and no forced redesign for a replacement. For dual-sourcing resilience, Vishay's SFH6186 family includes multiple CTR bin options (the '-5' bin is this one); a pin-compatible sibling with a different CTR bin may be qualified in parallel if the design can tolerate the CTR spread.