Optimal Choice for Phase Margin on mm-Wave PLL Frequency Synthesizer for 5G Wireless Communications Systems

One of the approaches for the next fifth generation (5G) is to utilize millimeter-wave (mmWave) spectrum in order to satisfy the future expected requirements, such as super high bit rate. For this, it will need to use high channel spacing. This paper presents a [81-86] GHz Integer-N frequency synthesizer using ultra wide bandwidth of channel spacing (1GHz) for 5G wireless communications systems. This work is focused on the impact of the phase margin loop filter on mm-Wave PLL frequency synthesizer performances. The choice of this parameter is an important criterion for the loop stability. It has an effect on the closed loop response, FM response and involves the design tradeoffs between the response time and the reference spurs. However, the obtained results of 45 degrees phase margin and 50 MHz comparison frequency indicate a noise density of -73 dBc, -89 dBc and -99 dBc at 50 MHz, 100 MHz and 150 MHz respectively, with 844fs RMS phase Jitter and temporal response of 936,631 ns.