Abstract
Two novel nonlinear CMOS transconductors that can be employed for building CMOS current-mode filters are presented and their performances compared to formerly proposed topologies aimed at the same goal. The first one is based on a previous topology proposed by the authors, where a new biasing procedure leads to an improved performance for low supply voltages. The second one follows a novel approach, based on cascading a transresistor and a transconductor. The analysis is complemented with a more general approach based on the identification of translinear loops present in the circuit. Both nonlinear transconductors can operate at supply voltages as low as one V GS plus two V DS of a saturated MOSFET. CMOS current-mode filters based on these blocks are built following companding techniques, and their correct operation is validated by simulation and experimental results.
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De La Cruz-Blas, C.A., López-Martín, A.J. & Carlosena, A. Low-Voltage CMOS Nonlinear Transconductors and Their Application to Companding Current-Mode Filters. Analog Integrated Circuits and Signal Processing 38, 137–147 (2004). https://doi.org/10.1023/B:ALOG.0000011164.33380.76
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DOI: https://doi.org/10.1023/B:ALOG.0000011164.33380.76