Isolation and switching for noisy bus lines
The HCPL0531R2 is a dual-channel optocoupler with a transistor output, rated for 2500Vrms isolation — enough to break ground loops in 24V industrial buses, PLC digital inputs, or motor-drive feedback paths. The 19% minimum CTR at 16mA forward current means the LED side needs at least 16mA drive to guarantee a logic-high on the output; if your microcontroller GPIO is current-limited below that, add a transistor buffer.
Switching speed and output drive
Typical turn-on time is 450ns, turn-off 300ns — fast enough for 1 MHz serial isolation or PWM feedback at a few hundred kHz, but not for high-speed fieldbus like EtherCAT. The output can sink or source up to 8mA per channel at 20V max; that drives a standard 5V or 3.3V logic input directly through a pull-up resistor, no level shifter needed.
Active production, ROHS3, and sourcing
The 8-SOIC package (0.154-inch width, 3.90mm) is a common footprint shared with other dual optocouplers.
The DC input type means it works with a simple series resistor from a logic or sensor output — no AC coupling or zero-crossing circuitry.