This application note refers to the AD7708 and AD7718. Data sheets specify the update rate for Σ-Δ ADCs. The update rate is the rate at which conversions are performed when a single channel is selected and the ADC is continuously converting. The update rate that can be used depends on the application in which the ADC is being used. The peakto-peak resolution of the device degrades as the update rate is increased. In a multichannel application such as a data acquisition system, conversions from several channels are read, i.e., each channel is selected in turn and a conversion is performed for that channel. In such an application, the rate at which conversions are performed is different compared to a single-channel system. This application note describes the switching procedure used by these parts.