Design of High-Precision Low-Power Interpolation Modules with Modified SINC Filters

Most high precision sigma delta DACs use SINC filters to provide large stop-band attenuation. They have the highest operating frequency in comparison to other stages and therefore consume most of the power in an interpolation filter. This paper presents a proper method for reducing the power consumption of a SINC filter. Multistage SINC filters with different stage orders can reduce the power consumption while simultaneously keeping the performance as high as that in the conventional case. A high precision sigma delta DAC is considered to verify the proposed method. Different compositions are examined to find the optimum structure, consisting of half-band, FIR droopcorrection, and SINC filters to increase the sampling rate by 128. The minimum stop-band attenuation of the implemented filters is more than 110 dB and the pass-band ripple is less than 0.0002 dB. The worst-case power and active area of these filters are calculated by implementing them using library of standard cells of a 0.18μm CMOS process.