Isolation voltage and signal integrity
The HCPL0501R2V provides 2500Vrms galvanic isolation between input and output — enough to separate a 24 V PLC field side from a 3.3 V or 5 V logic controller in industrial I/O modules. The DC input side drives the LED at a forward voltage of 1.45V typ, with a max continuous forward current of 25 mA. On the output side, the transistor with base can sink up to 8 mA per channel at a maximum collector-emitter voltage of 20V.
Switching speed and CTR selection
Typical turn-on time is 450 ns and turn-off is 300 ns, placing this part in the high-speed optocoupler class — suitable for isolated serial interfaces (e.g., RS-232, SPI) or fast digital I/O on a PLC backplane. The current transfer ratio (CTR) is specified at 16 mA forward current: minimum 19%, maximum 50%. That spread means the designer must bias the LED such that even at the low end of the CTR bin the output transistor saturates with the load current. For a 5V logic input, a 1.45V LED drop plus a series resistor sets the IF; the CTR then determines the available output current.
The part is available in Tape & Reel (TR) or Cut Tape (CT) in the 8-SOIC (0.154", 3.90mm width) package.