Functional Properties and Frequency Characteristics of Low-Sensitive RC Filters Based on Micropower Operational Amplifiers

Resumo

The main designs of low-sensitivity multiloop active RC filters (ARCFs) based on micropower operational amplifiers (OAs) for preliminary sensor signal processing in microelectronic measuring systems with analog-to-digital converters are discussed. Thirteen modifications of the integrators included in the active RC filter structure are presented and classified. The equations for their transfer functions, which take into account the effect of the integrator topology and the amplification area of micropower OAs, are obtained. As an example, the frequency responses of three universal low-sensitivity ARCF circuits for implementing bandpass, high-pass, and low-pass filters are compared. It is shown by computer simulation that the investigated ARCFs based on identical micropower OAs differ from each other in the effect of the amplification areas of the OAs on the implemented frequency responses.