All SC Blocks require a clock to operate their switched capacitor cells. This clock is called the column clock for each analog column. The column clock may be driven by VC1, VC2 or any digital block. In each analog column the column clock is further divided into 4 phases to drive the switches in the SC Block switched capacitor cells. So, the actual frequency at which the SC Blocks operate (Data Clock) is 1/4th the Column clock. For example, if the column clock to an ADC is 8MHz, the ADC would be actually operating at a data clock of 2MHz.