Isolation rating that sets the safety margin
The HMHAA280 delivers 3750Vrms isolation between input and output. The 4-SOIC package keeps the creepage distance tight.
AC/DC input simplifies the front end
Unlike many optos that only pass DC forward current, the HMHAA280 accepts both AC and DC input drive. That means a single device can sense an AC line zero-cross or a DC logic level without an external bridge or polarity diode. The forward voltage is 1.4V max at 50 mA — budget the series resistor for the input supply rail.
Temperature range and output drive
Rated from -55°C to 100°C, the HMHAA280 spans industrial and outdoor telecom enclosures without needing a separate extended-temp variant. The transistor output sinks up to 50 mA continuous at 80V max, with a typical 3 µs rise and fall time — fast enough for 100 kHz switching or PLC input sampling. Vce saturation is 400 mV max, so the voltage drop across the output at full load stays under half a volt.
Lifecycle and sourcing posture
Status is Active per onsemi's current product portfolio. ROHS3 compliant. The 4-Mini-Flat package (Supplier Device Package) is the same footprint as the 4-SOIC; both refer to the same physical part.