A 40 Gb/s Serial Link Transceiver in 28 nm CMOS Technology
Bibliographic record
Abstract
A 40 Gb/s serial link interface is presented that includes four lanes of transceiver optimized for chip-to-chip communication while compensating for 20 dB of channel loss. Transmit equalization consists of a 2-tap feed-forward equalizer (FFE) while receive equalization includes a 2-tap FFE using a transversal filter, a 3-stage continuous-time linear equalizer with active feedback, and discrete-time equalizers consisting of a 17-tap decision feedback equalizer (DFE) and a 3-tap sampled FFE. The receiver uses quarter-rate double integrate-and-hold sampling. The clock and data recovery (CDR) unit uses a split-path CDR/DFE design which facilitates wider bandwidth and lower jitter simultaneously. A phase detection scheme that filters out edges affected by residual inter-symbol interference allows recovering a low-jitter clock from a partially-equalized eye. A fractional-N PLL is implemented for frequency offset tracking. Combining these techniques, the digital CDR recovers a stable 10 GHz clock from an eye containing 0.8 UI p-p input jitter and achieves 1-10 MHz of tracking bandwidth. The transceiver achieves horizontal and vertical eye openings of 0.27 UI and 120 mV, respectively, at BER = 10 -9 . The quad SerDes is realized in 28 nm CMOS technology. Amortizing common blocks, it occupies 0.81 mm$^{2}$per lane and achieves 23.2 mW/Gb/s power efficiency at 40 Gb/s.
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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 | 0.000 |
| 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 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.010 | 0.005 |
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".