Implementation of Low-Noise Switched-Capacitor Integrators with Small Capacitors

Shigetaka TAKAGI

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E95-A    No.2    pp.447-455
Publication Date: 2012/02/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E95.A.447
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuit Techniques and Related Topics)
switched-capacitor circuits,  SC filters,  SC integrators,  noise transfer function,  

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A technique to reduce noise transfer functions (NTF) of switched-capacitor (SC) integrators without changing their signal transfer functions (STF) is proposed. The proposed technique based on a simple reconnection scheme of multiple sampling capacitors. It can be implemented into any SC integrators as long as they have a transfer delay. A design strategy is also given to reduce the effect of parasitic capacitors. An SC integrator with a small total capacitance and a low noise transfer gain based on the proposed technique is also proposed. For a given design example, the total capacitance and the simulated noise transfer gain of the proposed SC integrator are 37% and 90% less than the conventional one.