High-Efficiency Sigma-Delta Data Converters (SDMs)

This research line deals with the analysis, modeling, design, implementation and experimental characterization of Sigma-Delta Modulators (ΣΔMs) integrated in nanometer CMOS technologies. Different application scenarios are considered, spanning from sensor interfaces to broadband wireless communications. In these applications, a number of integrated circuits have been (or are being) developed, considering several circuit techniques, namely: discrete-time (switched-capacitor and switched-current), continuous-time (active-RC, Gm-C) and hybrid continuous-time/discrete-time circuits.

The research activities carried out in the last 5 years have been focused on the design of ΣΔMs intented for next-generation mobile communications and software defined radio. In these topics, the following Integrated Circuits (IC) prototypes have been developed:

  • A 130-nm CMOS 12-bit 40-MS/s 3-2 Cascade Continuous-Time ΣΔ Modulator (presented in the 2006 IEEE International Symposium on Circuits and Systems, ISCAS)
  • A 130-nm CMOS SC ΣΔ Modulator for GSM/UMTS/Bluetooth Multi-Standard Wireless Transceivers (presented in the 2007 IEEE Asian Solid-State Circuits Conference, A-SSCC)
  • A 90-nm CMOS 100kHz-10MHz BW, 78-to-52 dB DR, 4.6-to-11mW Flexible SC ΣΔ Modulator (presented in the 2010 IEEE European Solid-State Circuits Conference, ESSCIRC)
  • A 90-nm CMOS Power-Scalable Concurrent Cascade 2-2-2 SC ΣΔ Modulator for Software Defined Radio (presented in the 2012 IEEE International Symposium on Circuits and Systems, ISCAS)

The design of these ICs have been supported and fueled by diverse methodologies and CAD tools, specifically developed to systematize the synthesis and verification procedure and to optimize the performance in terms of target specifications with minimized power consumption. An example of these CAD tools is SIMSIDES, a time-domain behavioral simulator for SDMs developed in the MATLAB/SIMULINK environment (www.imse-cnm.csic.es/simsides). Since the first version of SIMSIDES was developed in 2003, the tool has been continuously updated and improved with new models and facilities, and has been freely distributed (under confidential conditions described in a NDA agreement) to a number of universities, research institutes and companies all over the world.

 

A 90-nm CMOS 100kHz-10MHz BW, 78-to-52 dB DR, 4.6-to-11mW Flexible SC ΣΔ Modulator

A 90-nm CMOS Power-Scalable Concurrent
Cascade 2-2-2 SC ΣΔ Modulator for SDR