Design of a Second-order Filter Using the \u3ci\u3eg\u3csub\u3em\u3c/sub\u3e-C\u3c/i\u3e Technique

This thesis deals with the design, layout, fabrication, testing and characterization of a second-order filter (biquad) using the transconductance-C (gm-C) technique. The biquad was designed to realize the four filter functions - lowpass, highpass, bandpass and notch - by appropriate choice of input and output terminals and element values. The tunable range of frequencies for the biquad was designed to be 18-59MHz. The quality factor of the biquad was designed to be tunable from approximately 1/3 to 3. The filter was designed in LEVEL2 SPICE, laid out using MAGIC, and the circuit was fabricated using MOSIS\u27s 2μm CMOS analog (n-well) process. The circuit board for testing the chip was designed using the PCB design system - PADS-PCB. The chip was tested using the Network Analyzer HP 4195A. The performance of the filter was then compared with the design objectives and simulation results. Both the pole frequency and the quality factor were found to be tunable by the same factor as the design. Noise analysis showed the output noise to be less than -65dB. The notch function could not be experimentally verified due to high sensitivity of this function to component tolerances and process variations. Power dissipation of the filter was found to be 6mW