A family of modular fully differential witched capacitor filters for simulating ladder filters

Abstract

SUMMARYThe switched capacitor filters proposed in this paper are based on the simulation of LC ladder filters through the state variable equations. They include all-pole and finite transmission zero, lowpass filters, bandpass and highpass filters. The introduced family of filters has a fully differential structure; consequently it has the advantages of improved power supply and common mode rejection ratios and extended dynamic range. Since the proposed family of filters simulates LC ladder filters, it inherits their low passband sensitivities. One of the main advantages of this family of filters is that it has a modular structure composed of key and auxiliary circuits. This modular structure results in easier design and implementation procedures in VLSI fabrication. The double-sampling concept is applied to the introduced modular blocks, which is essentially needed in high-frequency applications. A comparison with similar published work available in the literature is presented and illustrative examples are given.