1GHz Tuning Range, Low Phase Noise, LC Oscillator with Replica Biasing Common-Mode Control and Quadrature Outputs

摘要

The paper presents a low phase noise LC oscillator with 1GHz tuning range suitable for fiber optic transceivers and SDH/SONET (STM16/OC48 applications. In order to reduce power supply pushing and to have a well controlled common-mode with temperature and process, a replica biasing circuit regulates the common-mode voltage. The guaranteed tuning range covered with process and temperature variations is 2.2GHz-3.2GHz. A new concept of quadrature generation has been introduced. Measured results show a phase noise of -128dBc @ 3MHz @ 2.5GHz oscillation frequency. The measured quality factor of the coil is better than 20 @ 4GHz. Statistical analysis give 1σ deviation in the oscillation frequency of 12MHz (l% from the tuning range). The variation over temperature in the range (-45℃,+85℃) is only 20MHz, The typical power consumption of the VCO core is 18mW from a 3.3V power supply.