Shantanu Mehta - Academia.edu (original) (raw)
Related Authors
ISCTE - University Institute of Lisbon (ISCTE-IUL)
University of Physical Education in Cracow
Uploads
Papers by Shantanu Mehta
IEEE Open Journal of Circuits and Systems, 2021
Non-shaping dynamic element matching (DEM) randomization schemes are widely adopted for wideband ... more Non-shaping dynamic element matching (DEM) randomization schemes are widely adopted for wideband Nyquistrate digital-to-analog converters (DACs) within transmitter architectures. Here, randomization translates the mismatch-induced distortion into white noise from dc to F s /2 range. However, the DAC performance for various bands within the Nyquist range cannot be improved using non-shaped DEMs as their inherent structure cannot be made programmable. Conversely, mismatchshaping DEMs can be made tunable to shape the DAC errors over various signal bands, which makes them suitable for wireless transmitter applications. This paper presents the design methodology for high-order mismatch-shaping DEM architectures suitable for wideband Nyquist DACs. The challenge in designing high-order DEM structures for Nyquist DACs is to make them programmable to cover various signal bands within the Nyquist range and to operate them at high-frequencies demanded by the applications. Moreover, the stability of the high-order loop-filter within the DEM and its implementation cost is of great concern. This work details techniques to design programmable, stable, and hardware efficient high-order DEM structures for wideband Nyquist DACs. The DEM structures are implemented on an UltraScale+ FPGA device for prototyping and validation. Furthermore, the DEM design operation is validated by obtaining the measurement results interfacing with a 5-bit analog DAC.
2019 17th IEEE International New Circuits and Systems Conference (NEWCAS)
This paper presents a design of a low-latency 12-bit linear tri-level current-steering digital-to... more This paper presents a design of a low-latency 12-bit linear tri-level current-steering digital-toanalogue-converter for use in continuous-time ADCs. The DAC design achieves 12-bit static linearity, while the combination of DAC slice impedance matching with a proposed compensation technique reduces outputimpedance related distortion. The technique demonstrates ~10dB improvement in DAC dynamic performance at high frequencies over the Nyquist-band at 100MS/s. The DAC has been verified by simulation results in TSMC 1.2V 65nm CMOS technology.
2020 27th IEEE International Conference on Electronics, Circuits and Systems (ICECS), 2020
2021 IEEE International Symposium on Circuits and Systems (ISCAS), 2021
This paper presents a programmable amplitude and timing error shaping bandpass dynamic- element-m... more This paper presents a programmable amplitude and timing error shaping bandpass dynamic- element-matching (DEM) for Nyquist-rate D/A converters. Amplitude and timing-skew errors are shaped using two different loop-filters employed within the DEM structure. The systematic-duty-cycle errors are eliminated from the DAC spectrum using a controlled set of 'ON' transitions for any choice of the input-signal over the Nyquist band. The loop-filter order within the DEM can be selected to 2, 4 or 6 and the DAC errors can be shaped over a narrow or wide band for any choice of center-frequency. This work demonstrates that for a 12bit segmented Nyquist DAC (5T-7B), the in-band SFDR and IMD3 is >80dBs for the DEM configurations.
IEEE Open Journal of Circuits and Systems, 2021
Non-shaping dynamic element matching (DEM) randomization schemes are widely adopted for wideband ... more Non-shaping dynamic element matching (DEM) randomization schemes are widely adopted for wideband Nyquistrate digital-to-analog converters (DACs) within transmitter architectures. Here, randomization translates the mismatch-induced distortion into white noise from dc to F s /2 range. However, the DAC performance for various bands within the Nyquist range cannot be improved using non-shaped DEMs as their inherent structure cannot be made programmable. Conversely, mismatchshaping DEMs can be made tunable to shape the DAC errors over various signal bands, which makes them suitable for wireless transmitter applications. This paper presents the design methodology for high-order mismatch-shaping DEM architectures suitable for wideband Nyquist DACs. The challenge in designing high-order DEM structures for Nyquist DACs is to make them programmable to cover various signal bands within the Nyquist range and to operate them at high-frequencies demanded by the applications. Moreover, the stability of the high-order loop-filter within the DEM and its implementation cost is of great concern. This work details techniques to design programmable, stable, and hardware efficient high-order DEM structures for wideband Nyquist DACs. The DEM structures are implemented on an UltraScale+ FPGA device for prototyping and validation. Furthermore, the DEM design operation is validated by obtaining the measurement results interfacing with a 5-bit analog DAC.
2019 17th IEEE International New Circuits and Systems Conference (NEWCAS)
This paper presents a design of a low-latency 12-bit linear tri-level current-steering digital-to... more This paper presents a design of a low-latency 12-bit linear tri-level current-steering digital-toanalogue-converter for use in continuous-time ADCs. The DAC design achieves 12-bit static linearity, while the combination of DAC slice impedance matching with a proposed compensation technique reduces outputimpedance related distortion. The technique demonstrates ~10dB improvement in DAC dynamic performance at high frequencies over the Nyquist-band at 100MS/s. The DAC has been verified by simulation results in TSMC 1.2V 65nm CMOS technology.
2020 27th IEEE International Conference on Electronics, Circuits and Systems (ICECS), 2020
2021 IEEE International Symposium on Circuits and Systems (ISCAS), 2021
This paper presents a programmable amplitude and timing error shaping bandpass dynamic- element-m... more This paper presents a programmable amplitude and timing error shaping bandpass dynamic- element-matching (DEM) for Nyquist-rate D/A converters. Amplitude and timing-skew errors are shaped using two different loop-filters employed within the DEM structure. The systematic-duty-cycle errors are eliminated from the DAC spectrum using a controlled set of 'ON' transitions for any choice of the input-signal over the Nyquist band. The loop-filter order within the DEM can be selected to 2, 4 or 6 and the DAC errors can be shaped over a narrow or wide band for any choice of center-frequency. This work demonstrates that for a 12bit segmented Nyquist DAC (5T-7B), the in-band SFDR and IMD3 is >80dBs for the DEM configurations.