Design of 0.35-ps RMS Jitter 4.4–5.6-GHz Frequency Synthesizer with Adaptive Frequency Calibration Using 55-nm CMOS Technology

Abstract

This paper demonstrates the design and implementation of a 5-GHz frequency synthesizer using 55-nm complementary metal-oxide semiconductor technology. The proposed synthesizer achieves an ultra-low 0.35-ps jitter with a high-resolution adaptive frequency calibration scheme that automatically chooses frequency-tuning curves and improves calibration accuracy. The proposed synthesizer employs a high-Q LC voltage-controlled oscillator, constant bandwidth, low, and even $$K_{\mathrm{VCO}}$$ technique using thermometer-weighted capacitor calibration, a low-power divider, and a charge-pump (CP) circuit to achieve low jitter. The oscillator comprises a modified digitally controlled capacitor and varactor array, which extend the tuning range and minimize the phase noise. A matched differential CP is adopted to reduce reference spurs and phase-noise performance. The proposed frequency synthesizer achieves an output frequency of 4.4–5.6 GHz with a chip area of $$0.33\hbox { mm}^{2}$$ . The power consumption is 20 mW from a 1.2-V supply at 5 GHz, and the reference spur is −67.99 dBc. The measured root mean-square random jitter and phase noise are 0.35 ps and −110.04 dBc/Hz at 1 MHz, respectively.