A 40GHz PLL with −92.5dBc/Hz in-band phase noise and 104fs-RMS-jitter

This paper demonstrates a fully integrated low phase noise PLL at 40GHz, implemented in a 0.25-μm SiGe:C BiCMOS technology. An in-band phase noise improvement of 1.4dB to 3.2dB is measured across the locking range using the proposed double-gain PFD. The PLL achieves an in-band phase noise <;-92.5dBc/Hz and an integrated RMS jitter of 104fs, a 25% improvement over conventional PFD. The reference spurs are <;-73dBc across the whole locking range.