Isolation and signal transfer in a single channel
The FOD2741CSV is a 1-channel optoisolator from onsemi's FOD274 family, providing 5000Vrms galvanic isolation between a DC input LED and a phototransistor output. This isolation rating meets reinforced insulation requirements per IEC 60950-1, making it suitable for safety barriers in power supplies, motor drives, and industrial control interfaces where the primary and secondary sides must be electrically separated.
Current transfer ratio — what 100-200% at 10 mA means
The CTR is specified as 100% minimum and 200% maximum at a forward current of 10 mA. A CTR of 100% means the output transistor can sink at least as much current as the LED draws — so at 10 mA LED drive, the output can deliver 10 mA into the load. The 200% ceiling means the part is not overly sensitive, avoiding saturation or excessive gain in logic-level interfaces. This range suits standard TTL or CMOS input stages without external gain stages.
Output ratings — voltage and current limits
The phototransistor output is rated for a maximum collector-emitter voltage of 30 V and a continuous output current of 50 mA per channel. The Vce saturation voltage is 400 mV maximum at the rated current, which keeps the voltage drop low enough to drive a 5 V logic input directly. These limits define the load side: use it for signals up to 24 VDC and currents below 50 mA, typical for PLC digital inputs, relay drivers, or isolated feedback loops.
Package and temperature range
Housed in an 8-SMD Gull Wing package (supplier device package 8-SMD), the FOD2741CSV is designed for surface-mount assembly on standard PCB footprints. The part ships in Tube packaging.
onsemi has marked the FOD2741CSV as Obsolete. There is no official successor or second-source listed in the manufacturer's records. For existing BOM lines, availability is limited to surplus and broker inventory.