3750Vrms isolation in a 4-SMD gull wing
The Renesas PS2703-1-K-A is a single-channel phototransistor optocoupler from the NEPOC series, packing 3750Vrms isolation into a compact 4-SMD gull wing package. It takes a DC input on the LED side and switches a phototransistor output rated for 120V and 30mA per channel. The current transfer ratio is specified at 200% minimum and 400% maximum at a 5mA forward current, which gives the designer a predictable gain window for sizing the LED drive resistor and the pull-up on the output side. Rise and fall times are both 10µs typical, making this part suited for status feedback, relay replacement, and isolated logic-level translation at moderate speeds — think PLC digital inputs, motor drive fault signals, or medical equipment isolation barriers where the 3750Vrms rating meets basic safety isolation requirements.
CTR window — 200% to 400% at 5mA
The 200% minimum CTR at 5mA forward current means the phototransistor collector current will be at least 10mA when the LED is driven at 5mA, which is enough to saturate a typical 10kΩ pull-up to 5V or 3.3V. The 400% maximum cap prevents overdrive that could slow turn-off. At low forward currents below 1mA the CTR drops off, so if you are trying to save LED power, verify the CTR curve — the min/max spec is only guaranteed at 5mA. The 300mV Vce saturation at the rated output current keeps the logic-low voltage well within TTL and CMOS thresholds.
-55°C to 100°C — industrial cold, not full automotive hot
The operating temperature range is -55°C to 100°C.
It is ROHS3 compliant. No last-time-buy clock is ticking.