A phase-coherent transformer enabled 2:1 frequency divider with 7dB phase noise reduction and speed×gain/power F.O.M. of 2×10 (pico-Joule)-1

This paper demonstrates a phase-coherent transformer (PCT) enabled 2:1 22GHz frequency divider in 0.18 μm CMOS with 16 dB power gain and 7dB phase noise reduction. The PCT reverberates magnetic energy between the sensing and latching stages, resulting in extremely power efficient divider circuit topology. High division gain eliminates the use of consecutive buffer amplifiers. Consequently, the PCT divider enjoys low phase noise, low power consumption with a speed×gain/power F.O.M. of 2×10² (pico-Joule)^-1.