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Design and Implementation of a Low Power High Speed ADC Based on SAR ADC

Fazel, Ziba | 2015

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 47650 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Atarodi, Mojtaba; Saeedi, Saeed
  7. Abstract:
  8. ADC is one of the key functional blocks of any mixed signal system and therefore must be optimally designed concerning power, performance, resolution and silicon area. Among different architectures have been employed up to now, successive approximation register ADCs are known as the ones with lower power, more simplicity and lower sampling rate. Benefiting from scaling down the CMOS technology results in higher sampling rate and lower power SAR ADCs replacing other types of ADCs. To achieve the desired ADC performance, efforts are usually focused on the improvement of circuit techniques as well as on the introduction of new or combinational architectures based on SAR ADCs. This thesis aims to design an ADC suits an ultrasound application, too. Sharing an ADC among a number of channels is common in an ultrasound imaging systems. Need for an ADC with higher sampling rate for a high quality image and with lower power for minimizing the system power, encouraged us to proppose a novel structure based on pipelining SAR ADCs. A new way of passive residue transferring beside a new way of stages’ collabration is presented. Its sapling rate is threefold more than a conventional SAR ADC. Comparing it with alike structures, having same sampling rate and resolution, by formulting their characteristics show its lower power and smaller area.Attempt to minimize the effect of rising error sources in previous works is also done. For the first time in alike works, the linearity of ADC is formularized and analyzed demonstrating better linearity than a conventional one. A 7 bit of this architecture is also verified by post layout simulation results in 180-nm CMOS technology resulting better figure of merit than the others
  9. Keywords:
  10. Successive Approximation Register (SAR) ; Hybrid Structure ; Analog to Digital Converter ; Low-Power Design ; Pipline ; Passive Residue Transfer

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