Subharmonically Pumped RF CMOS Paramps

This paper discusses MOS-based RF integrated parametric amplifiers and converters (paramps). Specifically, MOS varactor characteristics are exploited to support subharmonically pumped configurations. Such configurations require lower frequency pumping, and thus, are more accommodating to CMOS pumps for millimeter-wave applications. Closed-form expressions are derived for the optimally biased accumulation-mode MOS varactor elastance based on pumping voltage, channel doping, and gate oxide thickness. Simple design equations for the pumped figure of merit, a metric common to all small-signal paramps, are obtained, resulting in a compact means of predicting integrated circuit performance. A comparison is made between MOS-based and diode-based designs (traditional and subharmonic) for a downconverting paramp topology. The importance of deep-depletion behavior is discussed.