These couplers are optically coupled isolation amplifiers that uses an IC with a high-accuracy Sigma-Delta A/D converter and a gallium aluminum arsenide (GaAIAs) light-emitting diode (LED) with high-speed response and high luminance efficiency on the input side, and an IC with a digital signal (MDAT, MCLK) output function on the output side. These couplers are designed specifically for high common mode transient immunity (CMTI) and high linearity (nonlinearity) applications, making them ideal for current sensing in motor drives.