5000Vrms isolation in an 8-DIP through-hole package
The HCPL4503M is a single-channel optocoupler from onsemi with a DC input and a transistor-with-base output, rated for 5000Vrms isolation. The 8-DIP (0.300", 7.62mm) through-hole package suits designs where a robust isolation barrier is needed between a low-voltage logic side and a higher-voltage power or field side — think motor-drive feedback, PLC digital inputs, or isolated serial interfaces.
Switching speed and CTR define the drive margin
The current transfer ratio (CTR) is specified at 16mA forward current: minimum 19%, maximum 50%. That 19% floor means the output side can sink at least 3mA when the LED is driven at 16mA — enough to pull a 5V logic input low through a 1.5kΩ pull-up. The 50% ceiling prevents saturation in high-gain loops.
Active production with a through-hole footprint
The 8-DIP through-hole package is less sensitive to moisture than small-outline surface-mount optocouplers — no MSL bake requirement for rework or long shelf storage. The 0.300-inch body width is a standard DIP footprint, so it drops into existing PCB layouts without a board spin.