Dual-channel optocoupler with wide CTR window
The onsemi FOD8802BR2 is a dual-channel transistor-output optocoupler from the OptoHit™ series, packing two isolated channels into a standard 8-SOIC package. It delivers 2500Vrms of galvanic isolation between the DC input and the transistor output, which is the baseline for basic isolation in industrial and power-supply applications. The current transfer ratio (CTR) is specified at 130% minimum to 260% maximum when driven with 1 mA forward current — a tighter bin than the broad commercial range, which reduces the spread in collector current across a reel and simplifies the bias resistor calculation in the receiver circuit.
What the switching speed means for your design
Rise and fall times are 6 µs and 7 µs typical respectively, with turn-on and turn-off times both at 6 µs typical. This places the FOD8802BR2 in the medium-speed class — adequate for 50/60 Hz line synchronisation, DC-link voltage sensing, and general-purpose logic isolation where the signal rate stays below ~10 kHz. It is not intended for high-speed digital isolation; a digital isolator or high-speed optocoupler would be needed above that bandwidth. The 75 V output rating and 30 mA continuous output current per channel cover most low-side switch and PLC digital input interfaces. The 400 mV maximum Vce saturation at the rated current keeps the voltage drop low enough to drive a 5 V logic input without an additional level shift.
Temperature grade and operating range
The CTR is specified at 1 mA drive across this range, so the minimum gain at the hot end is the figure to budget for worst-case collector current.