Active NEPOC optoisolator with 3750 Vrms isolation
The PS2701A-1-F3-A is a single-channel DC-input, transistor-output optoisolator from Renesas's NEPOC series. It provides 3750 Vrms of galvanic isolation between input and output, with a current transfer ratio (CTR) ranging from 50% to 300% at a forward current of 5 mA. The output transistor can handle up to 70 V and 30 mA continuous, with a typical Vce saturation of 300 mV.
CTR range and switching speed — design margin considerations
The 50% to 300% CTR range at 5 mA forward current is wide, which means the LED drive current can be optimized for power or speed, but the designer must account for the minimum CTR in worst-case calculations. For a given load, the LED current should be set to guarantee the output saturates even at the lowest CTR. Typical rise and fall times are 5 µs and 7 µs respectively, which is adequate for low-speed isolation applications like relay drivers, PLC inputs, or status feedback, but not for high-speed data links.
Package and footprint — 4-SOP Gull Wing
The PS2701A-1-F3-A comes in a 4-pin SMD package with Gull Wing leads, designated as 4-SOP by the supplier. The surface-mount footprint is compact and standard for this class of optoisolator. No special thermal management is needed for the 30 mA output current, but standard SMD soldering profiles for Gull Wing packages apply.