An integrated 0.6–4.6 GHz, 5–7 GHz, 10–14 GHz, and 20–28 GHz frequency synthesizer for software-defined radio applications

We present an integrated frequency synthesizer which is able to provide in-phase / quadrature phase signal over the frequency bands 0.6-4.6 GHz, 5-7 GHz, 10-14 GHz, and in-phase signal over 20-28 GHz for software-defined radio applications. Fabricated in a 0.25 mum SiGe-BiCMOS process, the synthesizer draws 45 mA from a 5 V supply and 160 mA from a 3 V supply. An integrated voltage controlled oscillator (VCO) with 34 % tuning range and a set of high speed dividers are used to accomplish all the frequencies. To achieve a wide tuning range while keeping a low gain and a low phase noise, the VCO employs digitally controlled sub-bands. The measured PLL phase noise is -108 dBc/Hz, -121 dBc/Hz and -135 dBc/Hz at 1 MHz offset for 24 GHz, 4 GHz and 700 MHz, respectively.