5000Vrms isolation — the design anchor
The Renesas PS8501-AX is a single-channel optocoupler from the NEPOC series, built for galvanic isolation in industrial and power-conversion applications. Its 5000Vrms isolation rating covers reinforced insulation requirements in motor drives, switch-mode power supplies, and PLC I/O modules. The transistor-with-base output gives the designer access to the base node for external biasing or Miller clamp — useful when you need to tailor the switching threshold or speed beyond the internal pull-up.
A minimum current transfer ratio of 15% at 16mA forward current means the output transistor can sink at least 2.4mA with 16mA in the LED — enough to drive a logic gate input or a small relay coil through a base resistor. The 8mA maximum output per channel and 35V output voltage rating suit 5V or 12V logic rails and low-power loads. If your load demands more current, you'll buffer with a transistor or a Darlington pair; the base-access output makes that easy.
220ns / 350ns switching — timing budget for the bus
Turn-on time of 220ns and turn-off time of 350ns place this part in the medium-speed optocoupler class — fine for 50 kHz PWM signals, serial data at 115.2 kbps, or status feedback in a control loop. The asymmetry (faster on than off) is typical for transistor-output couplers; account for it in your dead-time calculation if driving a half-bridge gate driver.
-55°C to 100°C — environment fit
It stops short of full military temperature (125°C), so check the thermal profile if the part sits near a heatsink or in a sealed enclosure with high ambient.
Package and mounting — through-hole legacy
Housed in an 8-DIP (0.300", 7.62mm) through-hole package, the PS8501-AX is a drop-in for existing socketed or wave-solder designs. Through-hole mounting means it fits prototype boards and legacy assemblies without a reflow profile change.