A 100–750 MS/s 11-Bit Time-to-Digital Converter With Cyclic-Coupled Ring Oscillator

This paper presents the first measured cyclic-coupled ring oscillator (CCRO) time-to-digital converter (TDC). The CCRO realizes a robust true time-domain delay interpolation with sub-gate-delay resolution. The architecture employs real-time quantization to reduce conversion time and hence maximize bandwidth. Furthermore, the CCRO phase progression is encoded with a bubble error suppression logic, thereby building resilience to delay mismatches from circuit/layout imperfections. The prototype circuit implemented in a 28 nm CMOS process demonstrates a combination of high resolution and high sample rate over wide range of sample rates. The TDC achieves its peak figure-of-merit (FoM) of 0.051 pJ/conv.-step at 100 MS/s while delivering 8.38-bit linear resolution and 15.4 ps time resolution, operating from a 0.55 V supply. The TDC demonstrates the highest reported linear resolution of 9.29 bits among converters operating above 100 MS/s, at 125 MS/s and 0.9 V supply, while achieving 4.4 ps time resolution and 0.16 pJ/conv.-step FoM. Further, the real-time quantizing architecture allows fast operation up to 750 MS/s, where the TDC delivers 6-bit linear resolution and 0.48 pJ/conv.-step FoM operating from 0.9 V supply.

Keywords

cyclic-coupled ring oscillator (CCRO), time-to-digital converter (TDC), sub-gate-delay, time resolution, bubble error, real-time, data converter

DOI

10.1109/ACCESS.2021.3068838

Citation

Jarvinen , O , Unnikrishnan , V , Siddiqui , W , Korhonen , T , Koli , K , Stadius , K , Kosunen , M & Ryynanen , J 2021 , ' A 100–750 MS/s 11-Bit Time-to-Digital Converter With Cyclic-Coupled Ring Oscillator ' , IEEE Access , vol. 9 , 9386109 , pp. 48147-48156 . https://doi.org/10.1109/ACCESS.2021.3068838

Permanent link to this item

https://urn.fi/URN:NBN:fi:aalto-202104072810

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[article-cris] Sähkötekniikan korkeakoulu / ELEC

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