A hardware efficient 3-bit second-order dynamic element matching circuit clocked at 300MHz

International audienceA robust and hardware efficient dynamic element matching (DEM) algorithm is developed and used to design a 4th-order bandpass (BP) mismatch-shaping circuit, moved inside the feedback loop of a 6th-order bandpass continuous-time delta-sigma modulator. This algorithm is based on a shortened tree-structured scheme (STDEM) which can assure a stable high order mismatch-shaping with a modest circuit volume. The modulator has a 3-bit quantizer and 8 thermometric feedback DAC's cells. The designed DEM's circuits is simulated in 0.35μ- CMOS which can be clocked up to 300-MHz. The mismatch error floor is decreased of about 35dB in the band of interest. Its related circuit occupies of about 0.22mm2 area

Calibration of DAC mismatch errors in sigma delta ADCs based on a sine-wave measurement

We present an offline calibration procedure to correct the nonlinearity due element mismatch in the digital-to-analog converter (DAC) of a multibit Sigma Delta-modulation A/D converter. The calibration uses a single measurement on a sinusoidal input signal, from which the DAC errors can be estimated. The main quality of the calibration method is that it can be implemented completely in the digital domain (or in software) and does not intervene in any way in the analog modulator circuit. This way, the technique is a powerful tool for verifying and debugging designs. Due to the simplicity of the method, it may be also a viable approach for factory calibration

Multi-stage noise shaping (MASH) delta-sigma modulators for wideband and multi-standard applications

Imperial Users onl

Contribución al modelado y diseño de moduladores sigma-delta en tiempo continuo de baja relación de sobremuestreo y bajo consumo de potencia

Continuous-Time Sigma-Delta modulators are often employed as analog-to-digital converters. These modulators are an attractive approach to implement high-speed converters in VLSI systems because they have low sensitivity to circuit imperfections compared to other solutions. This work is a contribution to the analysis, modelling and design of high-speed Continuous-Time Sigma-Delta modulators. The resolution and the stability of these modulators are limited by two main factors, excess-loop delay and sampling uncertainty. Both factors, among others, have been carefully analysed and modelled. A new design methodology is also proposed. It can be used to get an optimum high-speed Continuous-Time Sigma-Delta modulator in terms of dynamic range, stability and sensitivity to sampling uncertainty. Based on the proposed design methodology, a software tool that covers the main steps has been developed. The methodology has been proved by using the tool in designing a 30 Megabits-per-second Continuous-Time Sigma-Delta modulator with 11-bits of dynamic range. The modulator has been integrated in a 0.13-µm CMOS technology and it has a measured peak SNR of 62.5dB

Multibit delta sigma modulator with noise shaping dynamic element matching

Ph.DDOCTOR OF PHILOSOPH

A low hardware complexity time domain quantizer for wideband multibit - ADCs

This paper presents proof of concept of a low hardware complexity time domain quantizer (TDQ) for wideband multibit countinuous time (CT) ΣΔ ADCs. Besides rendering multi-level quantization of the input signal, the proposed scheme generates a two-level loop feedback signal for the modulator. The two-level feedback eliminates the errors emanating from component mismatches in the feedback digital-to-analog converter (DAC) due to process variations. The complete scheme is modeled using Simulink (MATLAB) and is validated through simulation. A 2nd order ΣΔ modulator incorporating the proposed TDQ achieves a dynamic range of 45.7 dB for a bandwidth of 10 MHz and an input sine-wave of -5.78 dBFS amplitude