5300Vrms isolation and CTR window
The SFH6156-2X001T: The 5300Vrms isolation rating qualifies this optocoupler for reinforced insulation in mains-connected circuits — it meets the creepage and clearance requirements for a basic isolation barrier in a 250 VAC line, and with proper PCB layout it supports reinforced insulation per IEC 60950-1 and IEC 62368-1. The current transfer ratio is specified as 63% minimum and 125% maximum at If=10 mA. That 63% floor is the number that drives the LED forward current budget: to guarantee the output transistor saturates into a 5 V logic input with a 10 kΩ pull-up, you need at least 63% × 10 mA = 6.3 mA collector current, which the 50 mA continuous output rating easily supports. The 125% ceiling matters when the LED is overdriven — excessive CTR can slow the turn-off time because the output transistor stores more base charge. If the application runs the LED at 20 mA and the output load is light, the transistor may saturate deeply and take longer to come out of saturation.
Switching speed and output drive
Typical rise and fall times are 2 µs each, with turn-on at 3 µs and turn-off at 2.3 µs. This limits the practical data rate to about 100 kbit/s in a standard logic interface — fast enough for a 9600-baud serial link, a PLC input filter, or a slow PWM gate drive, but not for a high-speed SPI or CAN bus isolator. The output transistor is rated for 50 mA continuous and 70 V across the collector-emitter. A 24 V PLC input sinking 5 mA, a 5 V logic gate with a 1 kΩ pull-up, or a small 12 V relay coil drawing 30 mA all fall within the SOA without an external driver transistor. Vce saturation is 400 mV maximum at the test current — that 0.4 V drop means the output low level is well below the 0.8 V threshold for TTL and the 1.5 V threshold for 5 V CMOS, so no level-shifting is needed on the output side.
Package, temperature range, and compliance
The 4-SMD Gull Wing package has visible solder joints — the leads splay out from the body, so you can inspect the fillet under a microscope and rework a single joint with a hot-air pencil without disturbing adjacent parts. The supplier device package is 4-SMD, meaning the body sits above the board surface by the lead standoff. Operating temperature covers -55°C to 100°C. The 100°C upper limit is the junction temperature — if the LED is driven at 20 mA and the output sinks 50 mA, the self-heating can add 20-30°C above ambient, so the actual ambient ceiling is around 70-80°C in a still-air enclosure. Below -40°C the CTR typically increases, so the minimum CTR at cold is not a concern. ROHS3 compliant with no exemptions — no deca-BDE, no phthalates, no lead in the solder terminations. The part carries the current lifecycle status of Active, meaning it is still a standard production item at Vishay, not a phase-out or NRND line.