Low phase noise Ku-band PLL-IC with −104.5dBc/Hz at 10kHz offset using SiGe HBT ECL PFD

This paper describes one of the lowest phase noise Ku-band PLL-IC below 10 kHz offset region using 0.18 ¿m SiGe-BiCMOS process. Since the phase frequency detector (PFD) generates the major portion of phase noise of total PLL in low offset frequency region, SiGe HBT emitter coupled logic (ECL) circuit is employed to reduce 1/f noise of the PFD. The fabricated PLL-IC achieves in-band phase noise of -104.5 dBc/Hz at 10 kHz offset in Ku-band. The calculated FOM (figure of merit) of -227.7 dBc/Hz² is the lowest value among the reported PLL-ICs at 10 kHz offset.