Highly Linear 2,5-V CMOS ΣΔ Modulator for ADSL+

We present a 90-dB spurious-free dynamic range sigma–delta modulator (ΣΔM) for asymmetric digital subscriber line applications (both ADSL and ADSL+), with up to a 4.4-MS/s digital output rate. It uses a cascade (MASH) multibit architecture and has been implemented in a 2.5-V supply, 0.25μm CMOS proc...

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Bibliographic Details
Authors: Río Fernández, Rocío del, Rosa Utrera, José Manuel de la, Pérez Verdú, Belén, Delgado Restituto, Manuel, Medeiro Hidalgo, Fernando, Rodríguez Vázquez, Ángel Benito
Format: article
Status:Versión aceptada para publicación
Publication Date:2004
Country:España
Institution:Universidad de Sevilla (US)
Repository:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/78365
Online Access:https://hdl.handle.net/11441/78365
https://doi.org/10.1109/TCSI.2003.821308
Access Level:Open access
Keyword:Analog-to-digital converters
ADSL
ΣΔ modulation
Switched-capacitor circuits
Description
Summary:We present a 90-dB spurious-free dynamic range sigma–delta modulator (ΣΔM) for asymmetric digital subscriber line applications (both ADSL and ADSL+), with up to a 4.4-MS/s digital output rate. It uses a cascade (MASH) multibit architecture and has been implemented in a 2.5-V supply, 0.25μm CMOS process with metal–insulator–metal capacitors. The prototypes feature 78-dB dynamic range (DR) in the 30-kHz to 2.2-MHz band (ADSL+) and 85-dB DR in the 30-kHz to 1.1-MHz band (ADSL). Integral and differential nonlinearity are within +/-0.85 and +/-0.80 LSB, respectively. The ΣΔ modulator and its auxiliary blocks (clock phase and reference voltage generators, and I/O buffers) dissipate 65.8 mW. Only 55 mW are dissipated in the ΣΔ modulator.