A design of narrow-band band-pass SCF´s using a pseudo-2-path principle and a capacitor-error-free voltage inversion

A design method is described for low-sensitivity narrowband bandpass switched capacitor filters (SCFs) using a pseudo-two-path principle and a capacitor-error-free voltage inversion. The proposed method is based on the low pass to high pass transformation using voltage inversion, the pseudo-two-path principle, the capacitance-ratio reduction technique, and a very low sensitivity low pass switched capacitor (SC) ladder filter configuration. A design example of the sixth-order bandpass SCF with a quality factor Q of the order of 200 is given in order to verify the proposed method. The features of this type of filter are low sensitivity to element-value variations (ideally, the worst case sensitivity becomes zero at every reflection zero), a small capacitance spread, a small total capacitance, and clock-feedthrough noise immunity inside the passband