The TLP621-4XSM optocoupler manufactured by Isocom is a series of optically coupled devices with a input and an output in a 4-pin DIP-SMD16 package. This optocoupler features RoHS compliance and state-of-the-art photoemission and photoconduction technology, which helps to reduce electric noise and improve reliability. This optocoupler is suitable for applications such as industrial machinery, computers, printers, home audio equipment, and many other electronic systems. The TLP621-4XSM has a high insulation voltage of 4,000Vrms, a CTR of 0.20A to 2.0mA, and a low on-resistance of 0.05ohm.