A 21 GHz Complementary Transformer Coupled CMOS VCO

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A new topology for low power voltage controlled oscillators (VCOs) using a 0.18-<formula formulatype="inline"><tex>$\mu{\hbox{m}}$</tex></formula> CMOS foundry process is presented in this letter. From the measured results, the VCO exhibits a tuning range of 3% at 21.3 GHz. Using complementary topology, the core power consumption and the output power are 9.6 mW and <formula formulatype="inline"> <tex>$-$</tex></formula>3 dBm, respectively. With the broadside coupled transformer, the VCO achieves a good phase noise of <formula formulatype="inline"><tex>$-$</tex> </formula>106 dBc/Hz at 1 MHz offset and a compact chip size of 350<formula formulatype="inline"><tex>$\,\times\,$</tex></formula>470 <formula formulatype="inline"> <tex>$ \mu {\hbox{m}}^{2}$</tex></formula>. It is the first time that the broadside coupled transformer approach is applied to transformer coupled CMOS VCOs. </para>