A novel coefficient automatic calculation method for sinc filter in sigma-delta ADCs

A novel coefficient automatic calculation (CAC) method for Sinc filter is proposed. Using CAC method, filter coefficients at full accuracy could be accessed with state transition and accumulator chain, without any coefficients storage. The illustrated method is an alternative to standard cascaded integrators and comb (CIC) approach and reaches maximum 41% power saving at cases. The performances of the proposed CAC and CIC approach are compared for general cases under different filter orders and decimation factors. Comparison shows that when filter order is low, the proposed CAC approach could be preferable for that in this case its power dissipation is much lower than CIC while keeping the acceptable area. All synthesis results are obtained under supply voltage of 1.62 V using TSMC 0.18 mum CMOS technology.