A 4th-Order 4-Bit Continuous-Time ΔΣ ADC Based on Active–Passive Integrators With a Resistance Feedback DAC
Bibliographic record
Abstract
This article reports a fourth-order continuous-time (CT) delta–sigma modulator (DSM) that features a single-amplifier biquad, a passive integrator, and an active integrator. This simplifies the circuit to only two op-amps in comparison to four power-hungry op-amps used in a conventional fourth-order DSM. In addition to improving the power consumption, the proposed design also has more relaxed requirements for the gain–bandwidth product and the loop gain. A 4-bit flash analog-to-digital converter (ADC) and two feedback digital-to-analog converters (DACs) are employed in this design to implement a fully integrated CT DSM. By incorporating the passive network in front of the last active integrator, this design gives a better attenuation at high frequency, which decreases the possibility of instability caused by out-of-band high-frequency signals. The proposed design has a measured bandwidth of 2 MHz with a power consumption of only around 3 mW. The effective number of bits (ENOB) of the proposed CT-DSM is approximately 12.7 bits with a peak signal-to-noise and distortion ratio (SNDR) around 78 dB, and it also exhibits a good Schreier figure of merit on the order of 166 dB compared to the existing state of the art.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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 teacher head, 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".