A 4–40MHz Active-RC chebyshev LPF with digital-assisted calibration for direct-conversion DVB-S/S2 & ABS-S TV tuners

A 4-40MHz fifth-order gain-adjustable LPF utilizing digital-assisted calibration for direct-conversion DVB-S/S2 & ABS-S TV tuners has been implemented in 0.13μm CMOS technology. The bandwidth of the filter can be changed from 4-16MHz with 0.5MHz step and 17-40MHz with 1MHz. The calibration includes automatic DC-offset Calibration (DCOC) and Automatic Frequency Tuning (AFT) to achieve less than 3mV residual output offset and 6% cut-off frequency deviation. The filter has -6-12dB gain range with 6dB step, less than 33.5nV/Hz^1/2 input-referred noise, 30dBm IIP3, 59dBm IIP2, and draws 10.7mA from 2.8V supply.