A Low Phase Noise Phase-Locked Loop With Short Settling Times for Automotive Radar

Abstract

This paper presents a millimeter-wave (mm-wave) synthesizer for use in the automotive band. The main focus is achieving low phase noise in conjunction with short settling times. By using a reference frequency of 1GHz, the synthesizer achieves a phase noise of lower than -105dBc/Hz at an offset frequency of 100kHz over the entire automotive band. The corresponding jitters, integrated from offset frequencies of 10kHz to 10MHz, are lower than 61fs. Simultaneously, with a loop bandwidth of 5MHz, a settling time of 880ns is determined for a frequency step with an error band of 10ppm. To improve linearity, the use of a static prescaler inside the loop was omitted. To the best of the author’s knowledge, this has not yet been achieved regarding a synthesizer using a fundamental VCO inside the automotive band.