What this optocoupler does in the assembly
The PS9513L3-AX is a single-channel optocoupler from NEC with a DC input and an open-collector output, providing 5000Vrms isolation between the input and output sides. It is designed for industrial signal isolation in applications such as PLC digital inputs, motor-drive fault feedback, and isolated communication interfaces where a 1Mbps data rate is sufficient. The open-collector output lets you pull the output line to any voltage within the 4.5V to 20V supply range, making it flexible for interfacing with 5V or 3.3V logic families through an external pull-up resistor.
Isolation and transient immunity — the real-world limits
Rated at 5000Vrms, this part suits reinforced isolation in industrial equipment where safety standards demand a high withstand voltage. The 15kV/µs common-mode transient immunity (CMTI) is the spec that matters in noisy environments like variable-frequency drives or inverter stages — it tells you the output won't glitch when a fast voltage transient jumps across the isolation barrier. At 1Mbps the propagation delay is 750ns max for low-to-high and 500ns max for high-to-low, which is fine for status feedback or low-speed data but too slow for high-speed fieldbus interfaces.
Package and mounting — shelf life and reflow
Housed in an 8-SMD Gull Wing package (supplier device package 8-DIP Gull Wing), it is a surface-mount part shipped in Tube form. The gull-wing leads are easier to inspect after soldering than J-lead or BGA packages.
Temperature range and operating environment
It does not reach the 125°C required for under-hood automotive or downhole applications, so keep it inside the conditioned panel or cabinet.