Serra H.A. de A., Paulino N. Design of Switched-Capacitor Filter Circuits using Low Gain Amplifiers

Springer, 2015. — 92 p.The objective of this book is to study switched-capacitor (SC) circuits based on the low-pass and band-pass Sallen-Key topologies, since they do not require high gain amplifiers. The strategy used to achieve this objective is to replace the operational amplifier (opamp) with a voltage buffer. Doing this simplifies the design of the amplifier although it also eliminates the virtual ground node from the circuit.Without this node parasitic insensitive SC networks cannot be used. Due to modern parasitic extraction software that can reliably predict the values of parasitic capacitances, the historical disadvantage of parasitic sensitive SC networks (parallel SC) is no longer critical, allowing its influence to be compensated during the design process.Switched-Capacitor Circuits
Low-Pass Filter Topologies
Band-Pass Filter Topologies
Non-Ideal Effects
Switched Capacitor Filter ImplementationAppendix A Butterworth Filtering Transfer Function
Appendix B Impulse Response Simulation and Bode Diagram Plotting