4000 Vrms isolation in a dual-channel SOIC-8
The Vishay ILD217T is a dual-channel transistor-output optocoupler in an 8-SOIC package, providing 4000 Vrms of galvanic isolation between a DC input and a transistor output. This isolation rating is typical for industrial interface applications where the logic side and the field side must be separated to prevent ground loops and protect low-voltage circuitry from transients on the power or sensor side.
CTR and switching speed — what matters for the BOM
The minimum current transfer ratio is 100% at a forward current of 1 mA. This means the output transistor can sink at least as much collector current as the LED draws — useful for driving logic inputs directly from a low-power GPIO without an extra gain stage. The 1 mA test condition also means the part works with low-drive microcontrollers that cannot source 10 mA per pin. Typical rise and fall times are 3 µs and 4.7 µs, with turn-on and turn-off times of 6 µs and 5 µs respectively. This puts the usable data rate in the low hundreds of kilohertz — fine for 24 VDC sensor readback, PLC discrete inputs, or isolated serial links at 115.2 kbaud, but not for high-speed fieldbuses. The maximum collector-emitter voltage rating of 70 V means the output side can handle 24 V industrial supplies with headroom for transients.
Temperature range and package integration
Rated for -55°C to +100°C operating ambient, the ILD217T covers industrial and some extended-temperature environments — motor-drive cabinets, outdoor telecom shelters, and engine-bay-adjacent electronics that see 85°C soak. The 8-SOIC footprint is a standard 0.154-inch-wide body with 3.90 mm width, compatible with most pick-and-place lines and reflow profiles.