Active, single-channel optocoupler for industrial isolation
The Renesas PS2911-1-F3-AX is a single-channel, DC-input, transistor-output optocoupler in a 4-Mini-Flat SMD package.
The current transfer ratio (CTR) is specified at 100% minimum and 400% maximum, both measured at a forward current of 1 mA.
Switching speed — adequate for 100 kbps, not for fast digital
Rise time is 5 µs typical, fall time 10 µs typical. Turn-on time is 40 µs, turn-off 120 µs.
Output ratings and temperature range
The output transistor is rated for 40 V maximum and 40 mA continuous per channel. Vce saturation is 300 mV maximum at the rated drive — low enough to pull a 5 V CMOS input cleanly to ground. Storage temperature is wider, but that's a handling limit, not an operating spec.
The 4-Mini-Flat package has flat leads — no gull-wing, no J-bend. That means the part sits flush on the PCB, which can help with low-profile designs but also means the leads are less compliant under thermal cycling. On a rework bench, a standard soldering iron with a fine tip can get to the pads, but you'll want to preheat the board to avoid cold joints.