BUY PC814. https://www.utsource.net/itm/p/5063291.html

Description: The PC814 is a four-pin optically-coupled isolator manufactured by Sharp. It is a small-sized, high-speed, and low-cost device that provides electrical isolation between two circuits. Features: Low input current of 1.6 mA High isolation voltage of 5,000 Vrms High speed of 1 μs Small package size of 4 pins Low cost High reliability Applications: AC/DC motor control Industrial automation Power supply control Signal transmission Medical equipment Automotive electronics (For reference only)