Skew analysis and bounded skew constraint methodology for rotary clocking technology

The square wave generated from the rotary operation with adiabatic switching is a continuously traveling wave, which provides multiple phases of the clock signal on the rotary ring. Recent research in the design automation of rotary clocking implementation has adopted some simplifications of the phase assignments for scalability. Towards this end, the design techniques, employed in conventional IC flows, can be employed for rotary clock automation as well. In this work, a timing framework is developed and skew analysis is presented for the rotary clocking technology to observe the effects of certain design simplifications in timing automation. Further, a methodology is presented to achieve a bounded skew implementation for rotary clocking technology. Experiments performed on R1-R5 benchmark circuits show a negligible increase in wirelength (around 1.25%) for the bounded skew constraint implementation with a 3.5% skew bound, where as, without the bounded skew, overall skew would be 5.5%.