低相噪、低功耗连续调谐双核压控振荡器

A low phase noise and low power consumption continuous tuning dual⁃core inductor⁃capacitive voltage⁃controlled oscillator (VCO) for Frequency Modulated Continuous Wave (FMCW) radar system is designed in GF 55 nm CMOS technology. The VCO couples the two oscillating cores and the buffer amplifier to each other through a three⁃coil transformer. Low phase noise is achieved by dual core operation with a wide continuous frequency tuning range. In order to reduce the high power consumption caused by the dual cores and provide high output power,we adopt center⁃tapped transformer and current reused technique to integrate cross couple pair and buffer amplifier. This circuit solves the problem of generally poor figure of merit (FoM) of dual⁃core coupled VCO. The post⁃simulation result shows that the VCO achieves a 13% continuous tuning range from 28 G~32 GHz,and the phase noise is as low as -105 dBc·Hz-1 at 1 MHz offset. Total dc power consumption including buffer amplifier is only 13.5 mW for 1.2 V supplied voltage. The peak output power is 4.5 dBm. The circuit achieves a FoM of 183 dBc·Hz-1.

Keywords： voltage⁃controlled oscillator ; dual core ; current reuse ; transformer