A 10-bit 500-KS/s low power SAR ADC with splitting comparator for bio-medical applications

This paper presents a 10b 500KS/s asynchronous successive approximation register analog-to-digital converter (SAR ADC) with input range prediction DAC switching technique for low power applications. The proposed input range prediction DAC switching technique narrows down the traditional try-and-error range of the input signal to prevent unnecessary DAC switching, and the average switching energy is 90% more efficient than the conventional approach. A prototype is fabricated in 0.18um CMOS technology. With a single supply of 1V, it achieves an ENOB, SNDR and FoM of 9.24b, 57.3dB, and 47fJ/Conversion-step at 500KS/s sampling rate, respectively.

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“…It is 20% more efficient than the energy-saving switching method in [8], and 90% more efficient than the conventional approach. Fig.…”

Section: Switching Algorithmmentioning

confidence: 94%

A 9.2b 47fJ/conversion-step asynchronous SAR ADC with input range prediction DAC switching

Huang

Lin

Hsieh

et al. 2012

2012 IEEE International Symposium on Circuits and Systems

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“…Adding to that, SAR ADC consumes less power and requires lower area to implement as compared to its other counterparts. All these features have made SAR ADC an unanimous choice in low power biomedical applications [12] [13] over the years. Since, the purpose that we need to fulfill requires a low power ADC with moderate resolution (~8-12 bits) and low sampling rate (~40kS/s), we believe SAR ADC is the most suitable choice.…”

Section: Motivation Of This Workmentioning

confidence: 99%

A 45 uW 13 pJ/conv-step 7.4-ENOB 40 kS/s SAR ADC for digital microfluidic biochip applications

Das

Sahoo

Roy

et al. 2014

18th International Symposium on VLSI Design and Test

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In recent years Digital Micro-fluidic Bio-chips have become a suitable choice for point of care diagnostics. These devices can detect various properties of human blood by means of an optical detection technique. The data acquisition is generally done using a LED-photodiode setup working in conjunction with the biochip. The voltage signal obtained at the photodiode output needs to be converted into digital data for further processing. A low power 8 bit SAR ADC is designed for this purpose and implemented in UMC 180 nm technology. The functionality testing of the ADC is done using Spectre simulator of Cadence Analog Design Environment. The ADC consumes about 45 μW of power at 13 pJ/conv-step from a 1.8 V supply at 40 kS/s and achieves a SNDR of 46.5 dB, ENOB of 7.4 bits at a signal bandwidth of 10 kHz. Mismatch analysis has been done by a set of Monte Carlo Simulations in Cadence. Even in worst case condition with 5% capacitance mismatch, the ADC achieves a SNDR of 43 dB, ENOB of 7 bits without any missing code.

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“…Increasing the ADC resolution requires larger capacitor arrays and increasing the capacitor switching energy. Several CDAC switching techniques, such as split capacitor [2], energy saving [3], monotonic [4], charge redistribution [5], Vcm-based [6], and switchback [7] have been researched to minimize the CDAC switching energy.…”

Section: Introductionmentioning

confidence: 99%

A 100-nW 9.1-ENOB 20-kS/s SAR ADC for Portable Pulse Oximeter

Lee

Park

Lim

et al. 2015

IEEE Trans. Circuits Syst. II

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This brief presents an energy-efficient 10-bit accuracy with 20-kS/s successive approximation register analog-to-digital converter (ADC) for portable pulse oximeter. A data-dependent capacitor reset (DDCR) switching scheme for the capacitive digital-to-analog converter (CDAC) to reduce the average switching energy and the number of unit capacitors is proposed and implemented. Compared to the conventional capacitor switching scheme for CDACs, the proposed DDCR switching scheme reduces the average switching energy and total number of unit capacitors by 97% and 75%, respectively. We achieved a signal-to-noise-and-distortion-ratio of 56.5-dB and a spurious-free dynamic range of 64.7-dBc at the Nyquist input frequency. The measured peak differential and integral nonlinearities are 0.44-and 0.58-LSB, respectively. The figure of merit is 9.1-fJ/conversion-step. The prototype, fabricated in the 0.11-μm CMOS process, occupies 0.033mm 2 .Index Terms-U-Healthcare, Pulse oximeter, analog-to-digital converter, successive approximation register, low-power, energy efficient.

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A 10-bit 500-KS/s low power SAR ADC with splitting comparator for bio-medical applications

Cited by 46 publications

References 5 publications

A 9.2b 47fJ/conversion-step asynchronous SAR ADC with input range prediction DAC switching

A 9.2b 47fJ/conversion-step asynchronous SAR ADC with input range prediction DAC switching

A 45 uW 13 pJ/conv-step 7.4-ENOB 40 kS/s SAR ADC for digital microfluidic biochip applications

A 100-nW 9.1-ENOB 20-kS/s SAR ADC for Portable Pulse Oximeter

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