1. Principle of switched-capacitor circuits

1.1 Simulating a resistor with a capacitor and two switches

In MOS integrated technology, we know how to make good operational amplifiers, fairly accurate capacitors (better than 10%) and analog gates, but we don't know how to make the inductors and resistors needed to synthesize analog filters. Feasible inductances have very low values (in the nanohenry range). Resistors are not very precise and have insufficient dynamic range if they are made by diffusion or in polysilicon, or, if they are made in the form of MOS channels, they are highly non-linear as a function of the voltage applied to their terminals.

The basic idea behind switched-capacitor filters is to replace resistors with a circuit comprising only capacitors and switches alternately opened and closed...

You do not have access to this resource.

Exclusive to subscribers. 97% yet to be discovered!

You do not have access to this resource.
Click here to request your free trial access!

Already subscribed? Log in!

The Ultimate Scientific and Technical Reference

A Comprehensive Knowledge Base, with over 1,200 authors and 100 scientific advisors

+ More than 10,000 articles and 1,000 how-to sheets, over 800 new or updated articles every year

From design to prototyping, right through to industrialization, the reference for securing the development of your industrial projects

This article is included in

Electronics

This offer includes:

Knowledge Base

Updated and enriched with articles validated by our scientific committees

Services

A set of exclusive tools to complement the resources

Practical Path

Operational and didactic, to guarantee the acquisition of transversal skills

Doc & Quiz

Interactive articles with quizzes, for constructive reading

Subscribe now!

Ongoing reading
Principle of switched-capacitor circuits

Previous
page Switched-capacitor filters

Analysis of switched-capacitor circuits

Bibliography

Basic works

ALLEN (P.E.), SANCHEZ-SINENCIO (E.) - Switched capacitor circuits - . 760 p., New York, Van Nostrand (1984).
HASLER (M.), NEIRYNCK (J.) - Filtres électriques - . Paris, 352 p., Dunod.
...

Analysis software

A number of analysis software packages are available, based on the principles of nodal analysis, to which refinements have been added to reduce calculation times and introduce the imperfections of active elements. Comparative analyses are available at

Examples of catalogued tours

Several manufacturers offer switched-capacitor biquadratic cells in the form of cataloged circuits. The best-known are the MF10 and LMF100 (National Semiconductor), containing two second-order biquadratic cells in a 20-pin package (DIP package) ...