Design of Low-Phase-Noise Low-Phase-Error CMOS Quadrature VCO

Two 2.4GHz LC quadrature voltage-controlled oscillators (QVCO) are designed. The advantages of the QVCO topologies are the characteristics of rather low phase error, while comparable phase noise is achieved. Phase noise of the two QVCOs are compared and analyzed. Simulation results show that phase noise improves 6.3dBc/Hz in a so-called PS-QVCO (PMOS-serial-coupled QVCO) compared to NS-QVCO (NMOS-serial-coupled QVCO). The PS-QVCO shows the phase noise of -115.4dBc/Hz at 600KHz offset, while dissipating only 2.9mW for the whole QVCO. The phase error between I and Q signals is at most 0.19°.