Realization of a monolithic integrator with improved high‐frequency response using a miller integrator and its application to filters

Abstract

AbstractRecently, various electronic devices have become smaller in size while being required to process signals at higher speed. Especially, monolithic integration of a high‐frequency active RC filter is expected.In this paper, a method is proposed for the design of a novel variable integrator in which a Miller integrator is introduced. It is demonstrated that, even though lateral PNP transistors are used, the high‐frequency characteristics are excellent.Next, the effect of the parasitic capacitance of the integration capacitor on the integration characteristics is investigated. It is shown that such an effect can be made negligibly small by an appropriate layout of the integration capacitor.Finally, by means of a circuit simulator PSPICE, the integrator and the third‐order Chebyshev lowpass filter designed with the integrators are simulated and the results are presented. Even though PNP transistors with a transition frequency of 7 MHz are used, good characteristics are obtained in a filter with a cutoff frequency of 2 MHz. In the case of a power supply voltage of 3.2 V and a cutoff frequency of 2 MHz. In the case of a power supply voltage of 3.2 V and a cutoff frequency of 2 MHz, the total harmonic distortion of the output voltage of the filter is less than 0.1 percent for the input signal voltage of 1 Vp‐p. Hence, the effectiveness of the proposed circuit is confirmed.