500MS/s 4-b time interleaved SAR ADC using novel DAC architecture

Sanjay Talekar1,  S. Ramasamy1,  G. Lakshminarayanan2,  B. Venkataramani2
1Mr., 2Dr.


The design and implementation details of a 4-bit time interleaved Successive approximation register (SAR) analog to digital converter (ADC) for UWB application is presented in this paper. Major contribution of this paper is the proposal for a novel digital to analog converter (DAC) architecture which reduces the area required for capacitors by a factor of three, while the maximum error due mismatch between capacitors is reduced by 33% compared to the architecture reported in the literature. The ADC is implemented in .18μm CMOS technology and has total power consumption of 17.6mw at sampling frequency of 500MS/s for an input swing of 1V peak to peak. Proposed SAR ADC gives SNDR of 23.7dB, SFDR of 31.5dB and THD of -32.2dB at Nyquist rate. The proposed ADC enables the input swing to be doubled while maintaining Figure of merit same compared to a SAR ADC reported in the literature.