Journal ArticleDOI
Passive SC Sigma Delta Modulators Revisited: Analysis and Design Study
Fahad Qazi,Jerzy Dabrowski +1 more
TLDR
The paper presents optimization of the modulator in the design space defined by the filter capacitor ratios and the feedback coefficients and shows that for this purpose the quantization and thermal noise should be considered jointly.Abstract:
In this paper we study passive switched-capacitor sigma-delta ( $\Sigma\Delta $ ) modulators suitable for low power applications. Using a one-bit quantizer as the only active block those modulators save power and achieve high linearity. However, their order is largely limited since the passive loop filter presents a significant attenuation to the signal. Typically with a second-order filter the modulator can achieve a satisfactory signal-to- quantization-noise ratio (SQNR) by using a large enough oversampling ratio (OSR) that also creates a tradeoff with the power consumption. A passive $\Sigma\Delta $ modulator when modeled as a linear system requires extraction of the equivalent loop gain. It is shown that for this purpose the quantization and thermal noise should be considered jointly. The paper presents optimization of the modulator in the design space defined by the filter capacitor ratios and the feedback coefficients. Both circuit and system level behavioral models are extensively exploited for this purpose. Provided is a detailed analysis of the thermal noise, quantization noise, and other parasitic effects. The design verified by 65 nm CMOS chip demonstrates very good agreement with the developed models. The measurements show signal-to-noise-and-distortion ratio (SNDR) of 73 dB and ${\hbox {power ~consumption}} with energy efficiency of 0.27 pJ/step at 0.9 V supply. For supply voltage reduced to 0.7 V the power consumption is 0.47 $\mu {\rm W}$ with ${\rm SNDR}= 71~{\rm dB}$ while energy efficiency is 0.16 pJ/step.read more
Citations
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Journal ArticleDOI
Continuous-Time Delta-Sigma Modulators Based on Passive RC Integrators
TL;DR: These techniques are based on increasing the contribution of the 1-bit comparator to the loop gain by using passive RC integrators together with low gain amplifiers in the loop filter of the continuous-time delta-sigma modulator, and it achieves 27.5 fJ/conv.-step of energy efficiency.
Journal ArticleDOI
Active–Passive $\Delta \Sigma $ Modulator for High-Resolution and Low-Power Applications
TL;DR: In this article, the use of a low gain amplifier and a passive switched-capacitor (SC) network to enable the SC integrator function is discussed, and the method is applied to a delta-sigma modulator to achieve high resolution.
Journal ArticleDOI
A low power passive-active ΔΣ modulator with high-resolution employing an integrator with open-loop unity-gain buffer
TL;DR: A new passive-active ΔΣ modulator with high-resolution and low-power applications is presented, using an open-loop unity gain buffer to improve the performance of a passive switch capacitor integrator.
Journal ArticleDOI
A 0.3 nW, 0.093%/V Line Sensitivity, Temperature Compensated Bulk-Programmable Voltage Reference for Wireless Sensor Nodes
TL;DR: In this article , a programmable CMOS-based voltage reference (VR) for wireless sensor nodes (WSNs) is proposed, where a body bias potential is used to control the threshold voltage of the nMOS current sink to generate programmable output voltage.
Journal ArticleDOI
Digital Calibration of Memory Errors in Passive Sigma-Delta Modulator
TL;DR: A digital adaptive calibration to compensate passive delta-sigma modulator error is proposed based on output-referred error model of passive integrator (PI) to show the effectiveness of the intrinsic error compensation of the modulator.
References
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Book
Understanding Delta-Sigma Data Converters
TL;DR: This chapter discusses the design and simulation of delta-sigma modulator systems, and some of the considerations for implementation considerations for [Delta][Sigma] ADCs.
Book
Delta-sigma data converters : theory, design, and simulation
TL;DR: Delta-Sigma Data Converters provides comprehensive coverage of low and high-order single-bit, bandpass, continuous-time, multistage modulators as well as advanced topics, including idle-channel tones, stability, decimation and interpolation filter design, and simulation.
Journal ArticleDOI
Spectra of quantized signals
TL;DR: Quantizing of time, or time division, has found application as a means of multiplexing telephone channels and the more familiar word “sampling” will be used here interchangeably with the rather formidable term “quantization of time”.
Journal ArticleDOI
Jitter analysis of high-speed sampling systems
TL;DR: The jitter of such practical sampling systems as analog-to-digital converters, sample-and-hold circuits, and samplers is discussed and a model for estimating jitter is proposed, based on sampling sine-wave signal- to-noise ratio calculations.