The onsemi 4N28SD is a single-channel optoisolator with a phototransistor output and base pin access, housed in a 6-SMD gull wing package on tape and reel. Rated for 5300Vrms isolation, it provides galvanic separation between a DC input LED and the output transistor stage — sufficient for reinforced insulation in mains-referenced control circuits. The minimum current transfer ratio is 10% at 10 mA forward current, with typical turn-on and turn-off times of 2 µs each, placing it in the general-purpose switching class for low-speed signal isolation.
Surface-mount 6-SMD gull wing footprint — the same 7.62 mm body width as the DIP-6 through-hole version, but with formed leads for reflow soldering. Check the MSL before you place it; the reel format suggests moisture-sensitive handling. Operating temperature range of -55°C to 100°C covers industrial and telecom environments, though the output transistor's 30 V maximum and 500 mV saturation limit the load side to low-voltage logic or small relay drives.
Available through independent distribution channels; quantities are lot-specific and confirmed at RFQ. The base product number 4N28 covers multiple package variants — verify the gull-wing SMD option matches your board layout before committing a BOM line.