Higher harmonic generation in CMOS/SOS ring oscillators

1 February 1982

journal article
Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Electron Devices

Vol. 29 (2) , 280-283
https://doi.org/10.1109/t-ed.1982.20696

Abstract

Harmonic generation is found with 101-stage ring oscillators. Harmonics have not been observed for the usual ring oscillators with a small number of stages. If one mistakes the higher harmonic generation for the fundamental, he obtains a wrong propagation delay which is shorter than the real one. It is shown experimentally and theoretically that only odd harmonics are generated for the ring oscillators with an odd number of stages. The propagation delay tpdof the nth harmonic oscillation is given byt_{pd} = n \cdot T/2NwhereTis the observed repetition period andNthe number of stages. Computer simulation shows that a ring oscillator with an even number of stages can also oscillate if every inverter is the same, and that the oscillation decays if there is asymmetry in the inverter chain. IfNis large and the effects of the deviations of the transistor parameters cancel one another, the harmonic oscillation that happens to be generated can continue.

Keywords

This publication has 4 references indexed in Scilit:

Effect of silicon film thickness on threshold voltage of SOS-MOSFETs
Solid-State Electronics, 1979
A CMOS/SOS Synchronous Static RAM Fabricated with an Advanced SOS Technology
Japanese Journal of Applied Physics, 1979
High performance MOS integrated circuit using the ion implantation technique
IEEE Journal of Solid-State Circuits, 1975
n-channel ion-implanted enhancement/depletion FET circuit and fabrication technology
IEEE Journal of Solid-State Circuits, 1973