Publication: Design of low noise amplifier and intermediate frequency amplifier for fm receiver ic
Loading...
Date
2007-05-01
Authors
Lim, Shyue Chyn
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Nowadays, the technologies used in producing transceiver are not good enough as they produce higher cost and power consumption transceiver. My main objective is to design good quality Low Noise Amplifier and Intermediate Frequency Amplifier, utilize only CMOS, that will be used in the implementation of the Single-Chip PLL-FM-Receiver. This is to develop the CMOS for RF application in producing low cost and low power consumption transceiver. Firstly, information will be gathered as much as possible to learn and design the LNA and IF amplifier. Then, the schematic diagrams will be drawn using the Cadence tools and simulations will be run on the circuits to observe their performance. Any improvement will be made whenever necessary to produce a better design of the amplifier. Finally, Cadence Virtuoso will be used to draw the layout of the finished design of amplifier circuits. The LNA is implemented with a single-ended LNA design that has a cascode common source topology with inductive source degeneration and a parallel resonant circuit consists of an inductor and a capacitor as load. Such load will provide an additional level of highly desirable bandpass filtering. The inductive source degeneration is employed to produce resistive input impedance for LNA. On the other hand, the IF amplifier is implemented with 6 stages of differential amplifier cascading together with a small unity-gain buffer exists in between each stage. Amplitude limiters are implemented in every single differential amplifier stage to limit the amplitude of amplified signal to only 1V since the demodulator is sensible to AM noise. The IF amplifier is closed loop with low pass filters as feedback in order to decrease the effect due to mismatch in components. The main results of my amplifier design is that the LNA has an input impedance of 61.5Ω (which will accommodate both the 50-Ω and 75-Ω antenna for broadcasting television and radio), a gain of 19.45dB, a noise figure of 2.36 dB, a low power consumption of 10.48mW and the IIP3 value of -15.9159 dB. Besides, the IF amplifier has a gain of 91.0253 dB at the intermediate frequency of 10.7MHz for a relatively small bandwidth of 69.29MHz. As a conclusion, there are 3 fields that future student can get to study them and improve their performance. These are the improvement of the linearity i.e. IIP3 of the LNA, the reduction of overshoot in the unit step response of LNA to improve its stability and the addition of testing pad at places in the amplifier circuits whenever necessary to increase the testability of the amplifier after fabrication.