Divider-less sub-sampling PLLs (SSPLL, Gao '10) and Injection-locked clock multipliers (ILCM, Elkholy '16) have demonstrated the best integrated jitter for a given DC power consumption. Achieving very low jitter-power figure-of-merit and reference spurs for wide PLL bandwidths is challenging as, in addition to the reduced filtering of the control voltage ripple resulting in reduced spur suppression, and that the bandwidth for optimal jitter can differ from that of fast settling requirements, the conditions of low spur can conflict with those of low jitter in these architectures. SSPLLs tend to have much better spurs, but even their very low jitter FoM is surpassed by large-injection ILCMs which eliminate all noisy loop components except the reference crystal. However, large injection results in very poor spur in the latter.
Jahnavi Sharma is a research scientist in high-speed communication links at Intel Labs in Oregon. SheÂ graduated with a bachelor's and master's degree in electrical engineering from the Indian Institute of Technology, Madras andÂ received her doctorate degree in electrical engineering at Columbia University. Her research interests include developing integrated circuit solutions for emerging applications, pushing performance through both system- and block- level innovation in CMOS and compound semiconductors. This also encompasses specific interests in high- to sub-mmWave circuit design, device modeling for high frequency design, and mixed-signal circuit techniques. Her doctoral work focused on signal generation for Â RF-to-Optical applications, and she was the recipient of the 2015-16 IBM PhD Fellowship Award. She was also selected for the 2016 Carnegie Mellon- MIT Rising Stars Workshop. She has also held internship positions at IBM in 2014 where she worked on widely-tunable mm-Wave oscillators in Silicon-Germanium, and at Alcatel-Lucent in 2013 and 2015 where she worked on designing cheap hybrid RF-mmWave modules for LTE fronthaul to improve network accessibility and higher data rates without expensive fiber-based backhaul.