Isolation and signal transfer
The H11A817B: Rated 5300Vrms isolation between input and output — this is the withstand voltage for reinforced insulation in mains-isolated feedback loops, SMPS secondary-side sensing, and PLC digital input modules where galvanic separation is mandatory. Current transfer ratio (CTR) is specified at 130% minimum to 260% maximum, measured at If=5mA — the wide band means the output transistor saturates reliably across the full temperature range without gain-stage redesign, but the minimum CTR sets the pull-up resistor ceiling in a given logic-family interface.
Output ratings and switching speed
Output transistor rated 70V Vce max and 50mA continuous collector current — suitable for driving 5V or 3.3V logic inputs through a collector resistor, or switching a low-current relay coil with a freewheeling diode.
Package and temperature grade
Housed in a 4-pin DIP with 0.300-inch (7.62mm) body width — the standard through-hole footprint that mates with 2.54mm-pitch sockets or solders directly into plated-through holes on a single-sided PCB.