Design and Implementation of an Inductor-Less Passive N-Path Balun

This paper outlines the design and measurements of a frequency-selective, tunable N-path balun with positive voltage gain using only switches and capacitors based on an N-path architecture. The balun has been fabricated in the GF 45RFSOI technology node with a clock path based on a Windmill frequency divider. The circuit operates in a frequency band ranging from 250 MHz to 1.25 GHz. It achieves a maximum measured 6.9-dB gain and a minimum 2.5-dB noise figure at 250 MHz for 1.2-m W power consumption. The maximum amplitude and phase imbalances are respectively 0.4 dB and 0.5°