CMOS Oscillators for Clock Distribution and Injection-Locked Deskew
Bibliographic record
Abstract
The distribution and alignment of high-frequency clocks across a wide bus of links is a significant challenge in modern computing systems. A low power clock source is demonstrated by incorporating a buffer into a cross-coupled oscillator. Because the load is isolated from the tank, the oscillator can directly drive 50-Ohm impedances or large capacitive loads with no additional buffering. Using this topology, a quadrature VCO (QVCO) is implemented in 0.13 mum digital CMOS. The QVCO oscillates at 20 GHz, consumes 20 mW and provides 12% tuning range. The measured phase noise is -101 dBc/Hz @ 1 MHz frequency offset. A clock alignment technique based upon injection-locked quadrature-LC or ring oscillators is then proposed. Although injection-locked oscillators (ILOs) are known to be capable of deskewing and jitter filtering clocks, a study of both LC and ring ILOs indicates significant variation in their jitter tracking bandwidth when used to provide large phase shifts. By selectively injecting different phases of a quadrature-LC or ring VCO, this problem is obviated resulting in reduced phase noise. The technique is demonstrated using a LC QVCO at 20 GHz while burning only 20 mW of power and providing an 8 dB improvement in phase noise. A ring oscillator deskews a 2 to 7 GHz clock while consuming 14 mW in 90 nm CMOS.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".