Browsing by Author "Bommalingaiahnapallya, Shubha"

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    Realizing analog circuits in digital processes
    (2011-06) Bommalingaiahnapallya, Shubha
    While the CMOS processes move to the nanometer regime and become more “digital” in nature, the consumer demands continue to focus on power-efficiency and reconfigurability. The optimal solution no longer lies only in the circuit design space. One has to consider architecture changes and look at the system as a whole. This thesis presents four such case studies. The multi-rate #6; − #1; ADC proposed in this thesis, is at its heart a multi-stage traditional #6; − #1; ADC where the first stage is running at ‘N’ times the sampling frequency. As ‘N’ tends to infinity, this approaches a hybrid #6; − #1; with a continuous-time(CT) front-end(FE). Thus, the new architecture exploits the best of both worlds - discrete and continuous. It has the clock-rate to power trade-off advantage of a discrete-time(DT) #6; − #1;. It also has anti-aliasing feature similar to the continuous-time(CT) #6; − #1; without its sensitivity to clock-jitter and EMI. In a similar architectural optimization, the position of the zeros of the noise transfer function (NTF) of a traditional #6; − #1; converter is altered by modifying the loop filter to create an N-Tone #6; − #1; converter. If the signals are then placed only in these noise valleys - a MC-OFDM, for example - a high signal-to-noise Ratio (SNR) can be achieved. In its most simplest form - the number of noise valleys being one - the N Tone #6; − #1; converter reduces to the familiar band-pass #6; − #1; converter. A low-power three-lane 231 −1 pseudo-random binary sequence (PRBS) generator is realized by multiplexing four appropriately delayed parallel sub-sequences running at one-fourth the data rate. The prototype achieves its low-power by amortizing the power of the PRBS core over the three lanes and by carefully partitioning out the overall architecture into CMOS and CML circuit spaces. Finally, a cost-effective low-jitter clock-distribution in a noisy environment is realized by making use of the well-known T-line clock distribution schemes on-die and moving the power distribution for the clock-network into the package.