A Modified High Phase Accuracy SIC-QVCO Using a Complementary-Injection Technique

This letter presents a complementary-injection-coupled technique to modify the conventional self-injection-coupled quadrature voltage-controlled oscillator (QVCO) topology. The proposed topology reduces the influence of dc offset problem at the source node of the coupling transistors that possibly makes the QVCO to fail and stop generating quadrature signals. Meanwhile, the modified coupling network provides an extra phase shift to resolve the bimodal oscillation. The QVCO is implemented in TSMC 0.18-μm CMOS technology. The measured phase noise is -111 dBc/Hz at 1-MHz offset, and the phase errors are from 0.29° to 1.39°. The figures of merit (FoM, FoM
_Q
) are -178.2 and -228.4 dBc/Hz, respectively. The chip area is 1.12 × 0.73 mm
²
.