The PS9551AL4 is an optically isolated Delta – Sigma Modulator that includes high-Accuracy A/D convertor and converts an analog voltage input into one-bit data stream. PS9551AL4 provides Effective Number of Bit (ENOB) is 12bits (typ) with a Sinc3digital filter. The PS9551AL4 is designed specifically for high common mode transient immunity (CMR) and high linearity (nonlinearity). The PS9551AL4 is suitable for current sensing and voltage sensing in motor drives.