A low-distortion anti-aliasing/smoothing filter for sampled data integrated circuits

The theory, the practical design, and the measurement results of a simple low-distortion continuous-time filter are discussed. The filter harmonic distortion and attenuation performances comply with the echo-cancelling MODEM specification. The circuit was designed in a conventional 4- mu m p-well double-poly CMOS technology. Based on the Sallen and Key structure, the proposed configuration achieves a second-order Butterworth low-pass transfer function with a minimum silicon area and a low parametric sensitivity.<
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