What this optoisolator is and where it fits
The FODM453R2 is a single-channel optoisolator from onsemi with a DC input LED and a phototransistor output. It provides 3750Vrms galvanic isolation between the input and output sides, which is the typical rating for basic isolation in industrial control, PLC digital inputs, and isolated sensor interfaces. The 5-Mini-Flat package saves board area compared to a standard DIP-8 opto, while still offering a creepage distance suitable for 3750Vrms isolation. The surface-mount footprint suits automated assembly lines.
CTR range and switching speed – what they mean for your circuit
Current transfer ratio (CTR) is specified at 20% minimum and 50% maximum, both measured at If=16 mA. The 20% floor is the number to use for pull-up resistor sizing and logic-level threshold calculations. Typical turn-on time is 400 ns and turn-off is 350 ns, giving a combined propagation delay of roughly 750 ns. This limits the usable switching frequency to about 500 kHz for a 50% duty-cycle square wave before pulse-width distortion becomes significant. For lower-speed signals like 24 VDC PLC inputs or relay coil drives, the speed is more than adequate.
Temperature grade and environment
Rated for -40°C to 85°C operating ambient, the FODM453R2 covers the industrial temperature range. This makes it suitable for outdoor telecom cabinets, factory-floor I/O modules, and motor-drive control boards. The maximum output voltage is 20V and the continuous output current per channel is 8 mA. These ratings match the typical 5V or 3.3V logic supply rails used on the secondary side of an isolated interface.
Sourcing and lifecycle status
The part is ROHS3 compliant, which satisfies the majority of global environmental compliance requirements for new designs. Available in Tape & Reel (TR) or Cut Tape (CT) options. The 5-Mini-Flat package is a standard SMD footprint; no special handling beyond normal MSL precautions is expected.