Abstract
Time-to-digital converters (TDCs) were historically used in laser range-finding, automatic test equipment, and timing jitter measurements, but recent developments in the design of high-resolution TDCs have paved the way for mostly digital implementation of PLLs and ADCs. Among the state-of-the-art TDCs, a flash TDC is the simplest, but its resolution is technology-limited by the minimum gate delay [1]. A pipelined TDC overcomes the technology limitation, but the characteristics of the inter-stage time-residue amplifier are inherently nonlinear and are therefore difficult to control in a robust manner [2]. A MASH TDC can improve the resolution by leveraging oversampling and noise shaping, but extracting the quantization error in the time domain poses many challenges [3]. A single-loop phase-domain continuous-time (CT) ΔΣ in [4] is susceptible to analog circuit imperfections. Furthermore, sampling frequency, F S, in all previous TDCs must be equal to the input carrier frequency, F C, which limits the over-sampling ratio (OSR) to be at most F C/(2xBandwidth). To overcome these drawbacks, we present a highly digital switched ring oscillator based TDC (SRO-TDC) that achieves noise shaping and is capable of operating at high OSRs. The prototype SRO-TDC achieves an integrated noise of 315fs rms in a 1MHz signal bandwidth at an input carrier and sampling frequencies of 80MHz and 500MHz, respectively while consuming less than 2mW from a 1V supply. It is also capable of operating over a wide range of input carrier frequencies (0.6 to 750MHz) and sampling rates (50 to 750MS/s).
Original language | English (US) |
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Title of host publication | 2012 IEEE International Solid-State Circuits Conference, ISSCC 2012 - Digest of Technical Papers |
Pages | 464-465 |
Number of pages | 2 |
Volume | 55 |
DOIs | |
State | Published - 2012 |
Externally published | Yes |
Event | 59th International Solid-State Circuits Conference, ISSCC 2012 - San Francisco, CA, United States Duration: Feb 19 2012 → Feb 23 2012 |
Other
Other | 59th International Solid-State Circuits Conference, ISSCC 2012 |
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Country | United States |
City | San Francisco, CA |
Period | 2/19/12 → 2/23/12 |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering