Linearity analysis and design optimization for 0.18um CMOS RF Mixer

Linearity analysis - Linearity analysis and design optimisation for 0.18pm CMOS RF mixer 0 Li and J.S Yuan Abstract Equations for the 1dB

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Linearity analysis and design optimisation 0.18pm CMOS RF mixer for 0. Li and J.S. Yuan Abstract: Equations for the 1dB compression point and third-order intermodulation point as a function of circuit and technology parameters are derived using a Volterra series expansion. The linearity analysis for both single- and double-balanced CMOS Gilbert mixers is examined. The relation between the input third-order intercept point and source inductance is studied in depth. The gate to drain overlap capacitance, which is one of the dominant nonlinear elements in a MOSFET, is included in the model. The design methodology to satisfy the mixer noise figure and conversion gain while optimising linearity is summarized. The analytical predictions are verified with the Cadence SpectreRF circuit simulation and experimental data. Good agreement between the model predictions and experimental data is obtained. 1 Introduction A CMOS RF up/down mixer results in a considerable increase in transceiver integration and a reduction in cost. The design of mixers faces many compromises between conversion gain, local oscillator (LO) power, linearity, noise figure, port-to-port isolation, voltage scaling and power consumption El]. Mixer linearity is a very important parameter in transceiver design, because system linearity is often limited by the first down-conversion mixer due to a relatively large signal compared with that at the LNA input. Since active FET mixers achieve conversion gain with lower LO power than their passive counterparts, the active CMOS single-balanced and double-balanced Gilbert mixers shown in Figs. 1 and 2 are commonly used in the CMOS transceiver design. Compared with the single-balanced counterpart, the double-balanced mixer has better port-to- port isolation due to symmetrical architecture. The double- balanced mixer has a higher noise figure due to more noise generators. The overall Gilbert mixer linearity is controlled primarily by the transconductance stage if the LO-driven transistors act as good switches. The linearity can be improved by using different degeneration. A good under- standing of linearity from different degeneration architec- tures is desirable for mixer design. Mixer nonlinearity of bipolar circuits using Volterra series analysis has been examined [2]. Short-channel MOSFET nonlinearity analysis using Taylor series expansion has also been presented [3]. The assumption of ideal memoryless transfer nonlinearities in the Taylor series analysis, however, is unrealistic. In this paper, RF nonlinearity equations using a Volterra series technique [4, 51 for both single and double-balanced CMOS Gilbert mixers with source degeneration are derived. It is commonly known that base collector capacitance C,, is 0 IEE, 2002 IEE Proceedings online no. 20020355 DOE 10.1049/ip-cds:20020355 PRper first received 10th November 2000 and in revised form 1st Noveniber 200 I The authors are with the Chip Design and Reliability Laboratory, School or Electrical Engineering and Computer Science, University of Central Florida, Orlando, Florida 32816, USA
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This note was uploaded on 12/04/2010 for the course ECE 123 taught by Professor Mais during the Spring '10 term at University of Calgary.

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Linearity analysis - Linearity analysis and design optimisation for 0.18pm CMOS RF mixer 0 Li and J.S Yuan Abstract Equations for the 1dB

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