3750Vrms isolation in a 4-SOIC footprint
The FODM217BR2V is a single-channel phototransistor optocoupler from onsemi's FODM217 series, delivering 3750Vrms galvanic isolation in a compact 4-SOIC package (4.40 mm body width). That isolation rating suits it for breaking ground loops and protecting low-voltage control logic from transient voltages on the secondary side — think PLC digital inputs, motor-drive feedback, or isolated sensor interfaces where the signal path stays under 80 V.
CTR range drives the LED bias design
The current transfer ratio is specified at 130% minimum to 260% maximum, both measured at If = 5 mA. That 2:1 spread means the designer must bias the input LED so that even at the minimum CTR the output transistor saturates into the load. At the 80 V output ceiling and 50 mA continuous output current, the device can drive a small relay coil or a logic gate input directly.
–55°C to 110°C — wider than commercial grade
Rated for –55°C to 110°C operating ambient, this part crosses into industrial and some automotive cabin environments. The 3 µs rise and fall times (typical at the stated test conditions) keep switching losses low in 10–100 kHz isolated data paths, though the phototransistor output is not intended for high-speed digital isolation — that is a digital isolator or optocoupler with a logic-output stage.
onsemi lists the FODM217BR2V as Active. ROHS3 compliant. No official successor or cross-reference is published — the part is current-production, so the BOM line can be committed without an end-of-life timeline. Sourced per RFQ; confirm current lead time and pricing at quote time.