No abstract

No abstract

Abstruct-Distortion in MOSFET-based (fixed-capacitance) continuous-time integrators is analyzed. To make the analysis general, the integrators are subdivided into four classes. Almost all the possible MOSFET integrators fall into one of these classes, the rest is mixed class. It is shown that integrators from the same class have the same distortion characteristics. A new method to describe and measure distortion is introduced. Measurement results for the four classes are presented, and for some classes they are explained with a simple MOSFET model. As not all results can be explained this way, a new, highly accurate MOSFET model is introduced. A hint at designing optimal MOSFET's is given. Finally, it is explained how the distortion characteristics of stages with different MOSFET's that all contribute to distortion can be determined.

No abstract

An eighth-order Butterworth bandpass filter, operating at 100 kHz with a quality factor of 14.3, is presented. The filter features an optimized dynamic range, a large tuning range, and a small occupied chip area of 0.25 mm2 owing to very simple circuitry. Measurements show a very accurate realization of the desired transfer function, a high dynamic range of 62 dB, and a tuning range from 50 to 200 kHz. It is shown how the dynamic range can be improved to a theoretical maximum if circuit simplicity is sacrificed.