Isolation and signal transfer for industrial and power interfaces
It comes in a 4-SMD gull-wing package for surface-mount assembly, with a 2.54 mm pin pitch (4-SOP). The part is active and ROHS3 compliant. With a current transfer ratio (CTR) range of 50% to 150% at 5 mA forward current, the SFH690AT guarantees a minimum output current drive across temperature and aging. The 50 mA maximum output per channel and 70 V collector-emitter rating suit it for logic-level isolation, PLC digital inputs, and low-power DC bus sensing.
Switching speed and drive margins for the BOM
Typical rise and fall times are 3 µs and 4 µs respectively, with turn-on and turn-off times of 5 µs and 3 µs. These figures place the SFH690AT in the standard-speed phototransistor class — adequate for 10-100 kHz isolated data transfer or for debouncing slow field signals like relay status or pushbutton states. The 300 mV maximum Vce saturation at rated current keeps the output voltage drop low, preserving headroom for the downstream logic threshold. Forward voltage is 1.15 V typical at 5 mA, and the LED can be driven up to 50 mA continuous, giving flexibility to adjust CTR by varying the input current. The 3750 Vrms isolation rating meets basic safety isolation requirements for reinforced insulation in many applications per IEC 60950-1 and UL 1577.