Design, Modelling and Simulation of a Fifth Order Low-Pass Gm-C Filter

The paper presents CMOS circuits for integrated analog filters at very high frequencies, based on transconductance integrators. The design of a higher order low-pass filter taking into account the types of approximations: Chebyshev and Butterworth, was made. The performances of the filters designed were demonstrated by implementing them using the biquads cascade synthesis method and the stare variable synthesis method. Starting either from the low-pass normalized poles, when using the cascading synthesis method, either from passive low-pass prototype normalized, when using the state variable synthesis method. The design of the transconductance cell has been done both at the model level and with transistors. All circuits have been simulated in order to prove the correct operation when implemented in a modern CMOS fabrication technology. As a technical contribution, can be noted the implementation and dimensioning of the main circuits, such as the polarization circuit, the operational amplifiers, the transconductance amplifier with active degeneration, applying improvements to the structure presented, checking the performance parameters and comparing the results.