What this optoisolator is and where it fits
The Renesas PS2561DL2-1Y-V-A is a single-channel photocoupler from the NEPOC series, pairing a DC-input LED with a phototransistor output in a 4-SMD gull-wing package. It delivers 5000Vrms of galvanic isolation between primary and secondary sides, making it a standard choice for breaking ground loops and protecting low-voltage control logic from high-side transients in power supplies, motor drives, and industrial I/O modules.
5000Vrms isolation and the temperature envelope
The 5000Vrms isolation rating is the headline spec for this part — it provides reinforced insulation suitable for mains-referenced circuits where safety isolation is required between the control and power stages. The operating temperature range of -55°C to 110°C covers most industrial environments, outdoor telecom cabinets, and equipment near heat sinks or motor windings. At the cold end, the LED forward voltage (1.2V typical) and CTR remain stable enough for reliable turn-on down to -55°C.
CTR range and drive margin
Current transfer ratio is specified at 50% minimum to 400% maximum, both measured at 5mA forward current.
Output ratings and switching speed
The output transistor is rated for 80V maximum collector-emitter voltage and 50mA continuous current per channel. That 80V ceiling handles 24V industrial rails, 48V telecom buses, and most auxiliary supply voltages with margin. Vce saturation is 300mV max, which keeps the logic-low level clean for 3.3V or 5V digital inputs. Rise and fall times are 3µs and 5µs typical — this is not a high-speed digital isolator; it suits status feedback, fault signalling, and low-frequency PWM (under a few kHz) rather than high-rate data links.
Package and mounting
The 4-SMD gull-wing package (supplier device package 4-SMD) is a standard surface-mount photocoupler footprint. The gull-wing leads provide good visual solder-joint inspection access. The tube shipping medium is typical for this package size; if the line runs tape-and-reel feeders, verify the reel-pack variant of the same die.
Lifecycle and compliance
The part carries an Active product status and is ROHS3 compliant. No end-of-life notification or last-time-buy window is in effect. This is a standard-production NEPOC series part.