Design of a 14-bit continuous-time Delta-Sigma A/D modulator with 2 5MHz signal bandwidth /
In recent years, there has been growing interest in both industry and academia to use continuous-time (CT) [Delta]-[Sigma] A/D converters for wideband wireless and wireline communication applications. So far no reported CT [Delta]-[Sigma] A/D modulator achieves 14-bit or higher dynamic range (DR) with more than 2MHz signal bandwidth (equivalently 4MS/s). This dissertation presents the realization of a continuous-time (CT) [Delta]-[Sigma] A/D modulator providing 80.5dB SNDR and 85dB DR with 5MS/s output data rate in a 2.5V 0.25æm CMOS process. The modulator has a single-stage dual-loop architecture allowing large quantizer delay. A 17-level quantizer is used to increase resolution and non-return-to-zero DACs are adopted to reduce clock jitter sensitivity. Capacitor tuning is utilized to overcome time-constant variation. On-chip self-calibration is implemented to suppress DAC nonlinearity. Combining techniques to address various design challenges, the modulator consumes 50mW with 60MHz sampling rate.
School:Oregon State University
School Location:USA - Oregon
Source Type:Master's Thesis
Keywords:analog to digital converters modulators electronics signal processing
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