A Wideband Merged CMOS Active Mixer Exploiting Noise Cancellation and Linearity Enhancement

Abstract

A wideband CMOS active mixer is proposed with improved noise and linearity, merging a resistive feedback noise-canceling low-noise amplifier as its transconductor. The noise-canceling characteristic enables the transconductor with low noise over a wide frequency range. An auxiliary pMOS transistor is employed to cancel the third-order nonlinear currents of a composite transistor in the transconductor, and impair the second-order nonlinear currents of that. To enhance input equivalent transconductance, a bulk cross-coupled feedback is applied to the transistor in the transconductor with large power consumption. Together with a current bleeding technique, comparable gain, noise, and improved linearity are achieved, but by reduced bias currents of the mixer. Fabricated in a 0.13- μm triple-well RF CMOS process, the proposed mixer demonstrates a voltage gain of 16.3-14.4 dB, average noise figure of 4.2 dB, and input-referred third-order intercept point of 7.3-2.5 dBm, operating between 500 MHz-5.8 GHz. It consumes 17 mA from a 1.5-V supply and occupies an area of 1.1×1.1 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .