Single-channel 5000Vrms isolator for industrial I/O
The Renesas NEPOC PS2561A-1-H-A is a single-channel phototransistor optoisolator in a through-hole 4-DIP package. It provides 5000Vrms of galvanic isolation between a DC input LED and a transistor output, making it a straightforward choice for breaking ground loops in industrial digital I/O, PLC input modules, and AC mains detection circuits. The current transfer ratio (CTR) is specified at 80% minimum and 160% maximum when the forward LED current is 5mA — a tight bin that gives predictable logic-level drive without over-designing the input-side resistor. Output transistor is rated for 70V collector-emitter and 30mA continuous current, with a typical Vce(sat) of 300mV. Rise and fall times of 3µs and 5µs respectively keep switching clean for low-speed optocoupler applications up to about 100 kbps.
The through-hole 4-DIP body (0.300" lead spacing) is a standard footprint — easy to hand-assemble or wave-solder in legacy production lines.
For dual-sourcing, the PS2801C-4-V-A is a surface-mount quad-channel sibling with the same 300mV Vce(sat) and similar CTR, but its 2500Vrms isolation and SOIC-16 footprint are a different board fit.