10 Mbps open-collector optocoupler with 3750 Vrms isolation
The Renesas PS9124-V-F3-AX is a single-channel optocoupler with a DC input and an open-collector output, rated for 10 Mbps data rate and 3750 Vrms isolation voltage. It comes in a 6-SOIC package with 5 leads (supplier device package 5-SO) for surface-mount assembly. Common-mode transient immunity is specified at a minimum of 10 kV/µs, which is the key spec for keeping data clean in motor-drive and inverter environments where fast voltage transients are present.
Open collector output — plan the pull-up resistor
The output can sink up to 25 mA per channel, so the pull-up value should be chosen to keep the sink current within that limit while meeting the rise-time requirement at 10 Mbps. With a typical rise time of 20 ns and fall time of 5 ns, the output transitions asymmetrically — the open collector pulls down fast but relies on the pull-up to charge the load capacitance. For a 5 V supply and a 10 pF load, a 1 kΩ pull-up gives roughly a 10 ns RC time constant, which is adequate for 10 Mbps. The 75 ns max propagation delay is the same for both low-to-high and high-to-low transitions, simplifying timing budget calculations.