5000Vrms isolation — the rating that defines the part
The Renesas NEPOC PS2561DL2-1Y-A is a single-channel transistor-output optocoupler rated for 5000Vrms of galvanic isolation. That isolation voltage is the headline spec — it tells you this part is built for reinforced insulation in industrial power supplies, motor drives, PLC digital inputs, and any application where a clean safety barrier between a low-voltage control side and a high-voltage power side is non-negotiable. The 4-SMD Gull Wing package keeps the creepage distance long enough to support that rating in a surface-mount assembly.
CTR range — 50% to 400% at 5mA forward current
The current transfer ratio spans 50% minimum to 400% maximum, both specified at 5mA LED forward current. That wide spread is typical for a standard-transistor optocoupler — you design the feedback loop or logic input around the minimum CTR to guarantee operation over temperature and LED aging. The 1.2V typical forward voltage and 40mA absolute-max forward current define the LED drive budget; a 5mA drive is a safe operating point that keeps the LED well within its ratings while delivering enough photocurrent to saturate the output transistor.
Output ratings — 80V, 50mA, 300mV saturation
The output transistor can handle up to 80V collector-emitter and 50mA continuous current, with a maximum saturation voltage of 300mV. That combination makes it suitable for driving a relay coil, a logic gate input, or a DC load in an I/O module. The 3µs rise and 5µs fall times (typical) cap the useful switching speed — this is not a high-speed digital isolator; it is a robust, slow-switching part for 50/60 Hz line-frequency signals, status feedback, or slow digital buses like a few hundred hertz PLC inputs.
Temperature range — -55°C to 110°C operating
Rated for -55°C to 110°C operating temperature, this optocoupler covers industrial, outdoor telecom, and automotive cabin environments without needing a commercial-grade derating. The wide range also simplifies BOM consolidation — one isolation part for a product line that ships into both heated factories and unheated enclosures.
Lifecycle and compliance — active, ROHS3
The NEPOC series is Renesas's optocoupler family; the PS2561DL2-1Y-A is a single-channel, DC-input, transistor-output variant in the surface-mount Gull Wing package.