Analysis and mitigation of timing inaccuracies in high-frequency on-chip sinusoidal signal generators based on harmonic cancellation

On-chip sinusoidal signal generators are a key element for enabling a wide variety of DfT and BIST applications for AMS-RF integrated circuits. Harmonic cancellation techniques have been recently proposed for the efficient implementation of high-quality embedded sinusoidal signal generators. However, harmonic cancellation techniques, based on phase-shifting and combining a set of periodic signals, rely on precise and accurate phase-shift control which makes them very sensitive to timing issues due to mismatch, noise, etc. Timing issues can severely limit the performance of these generators especially in high-frequency applications where precise timing becomes challenging. In this paper, we analyze the effects of timing inaccuracies on high-speed harmonic cancellation generators and we propose circuit techniques for mitigating them. Electrical simulation results on a 1.45 GHz sinusoidal signal generator implemented in ST 28 nm FDSOI technology are provided to validate our proposals.