Last-buy lifecycle and sourcing
The 4N28TVM carries a Last Buy status from onsemi — the manufacturer has announced end-of-life, and remaining inventory is being drawn down. Expect lot-specific date codes and sealed-reel or bulk packaging as available.
4170Vrms isolation and switching performance
Rated for 4170Vrms isolation between input and output — this is a reinforced-grade isolation barrier for galvanic separation in industrial controls, motor drives, and power-supply feedback loops where the primary side must be kept electrically isolated from the secondary control logic. Typical turn-on and turn-off times are 2 µs each, which supports switching up to roughly 250 kHz in a digital isolator role — adequate for most PLC input modules, relay drivers, and isolated serial interfaces.
CTR floor and drive requirements
Minimum current transfer ratio is 10% at 10 mA forward current — meaning with 10 mA through the LED, the output transistor can sink at least 1 mA. This sets the minimum load resistance and the worst-case drive margin for the downstream logic or relay coil. Forward voltage is 1.18V typical, and the LED can handle up to 60 mA continuous DC forward current — the 10% CTR floor is specified at 10 mA, so the LED drive current should be set between 10 mA and 60 mA to guarantee the CTR across temperature and device spread.
Through-hole DIP package and temperature grade
Housed in a 6-pin DIP with 0.400-inch (10.16 mm) body width — the wider DIP footprint provides extra creepage distance across the package surface, supporting the 4170Vrms isolation rating. The through-hole mounting suits hand-assembly or wave-solder processes in low-volume or prototype builds. The output transistor saturates at 500 mV maximum (Vce), keeping power dissipation low in the on-state.