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A continuous time delta-sigma modulator with reduced clock jitter sensitivity through DSCR feedback

  • Dejan RadjenEmail author
  • Pietro Andreani
  • Martin Anderson
  • Lars Sundström
Article

Abstract

The performance of continuous time delta-sigma modulators is limited by their large sensitivity to feedback pulse-width variations caused by clock jitter in their feedback DACs. To mitigate that effect, a dual switched-capacitor-resistor feedback DAC technique is proposed. The architecture has the additional benefit of reducing the typically high switched-capacitor-resistor DAC output peak currents, resulting in reduced slew-rate requirements for the loop-filter integrators. The feedback technique has been implemented with a third order, 3-bit delta-sigma modulator for a low power radio receiver, in a 65 nm CMOS process, where it occupies an area of 0.17 mm2. It achieves an SNDR of 70 dB over a 125 kHz bandwidth with an oversampling ratio of 16. The power consumption is 380 μW from a 900 mV supply.

Keywords

Delta-sigma Clock jitter Continuous time Peak current Switched-capacitor-resistor 

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Copyright information

© Springer Science+Business Media, LLC 2012

Authors and Affiliations

  • Dejan Radjen
    • 1
    Email author
  • Pietro Andreani
    • 1
  • Martin Anderson
    • 2
  • Lars Sundström
    • 2
  1. 1.Lund UniversityLundSweden
  2. 2.Ericsson ABLundSweden

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