10 Mbps open-collector isolation channel
The PS9117A-AX is a single-channel digital optocoupler from the Renesas NEPOC series, delivering 10 Mbps data rate with 3750 Vrms isolation in a compact 5-lead SOIC package. The open-collector output interfaces directly with 5 V logic families — no external level translation needed for TTL or CMOS inputs on the receiving side.
Timing and transient immunity for noisy environments
Propagation delay is 75 ns max in both directions (tpLH / tpHL), which sets the timing budget for a closed-loop control loop — at 10 Mbps the bit period is 100 ns, so the delay consumes 75 % of the window, leaving 25 ns for the receiver to sample. Rise and fall times of 20 ns typ and 5 ns typ respectively keep the output edges sharp enough to avoid metastability in the downstream flip-flop. Common-mode transient immunity is a minimum 15 kV/µs — this is the key spec for motor-drive and inverter applications where fast-switching IGBTs couple kilovolt-per-microsecond common-mode spikes across the isolation barrier. The PS9117A-AX rejects transients at that rate without corrupting the output state, preventing false trips on the controller side. The open-collector output sinks 25 mA per channel, sufficient to drive a 5 V relay coil through a current-limiting resistor or to pull down a 2.2 kΩ pull-up to 5 V with margin. The LED forward voltage is 1.65 V typ at 30 mA max forward current — a 330 Ω series resistor from a 5 V rail limits the LED current to about 10 mA, well within the safe operating area.