A New Structure of 8-Bit 60 MS/s SAR-ADC Using a Reduced Switching Capacitor-DAC Array

Author(s):  
G. Prathiba ◽  
M. Santhi

This paper presents an analysis of the Reduced Switching Capacitor Digital-to-Analog Converter (RSC-DAC)-based low power Successive Approximation Register Analog to Digital Converter (SAR-ADC). The proposed structure involves the Low voltage Static D-Latch Comparator (LSD-LC) with pre-amplifier operators in two modes (Normal and Hold), the RSC-DAC switching energy, reduced by 93% contrast to the standard Charge Redistribution Switching Capacitor DAC (CRSC-DAC) method, and the Successive Approximation Register (SAR) control logic. The LSD-LC with pre-amplifier consists of a latch circuit and a pre-amplifier. The pre-amplifier is often used to eliminate the DC offset voltage and kickback noise without substantially weakening the Signal-to-Noise Ratio (SNR) to drive the main circuit while the latch is needed for comparison. The linearity parameters such as Integral Nonlinearity, Differential Nonlinearity and effect of parasitic capacitances of the RSC-DAC are analyzed and improved by the new approach named as Adaptive Random Code Generation (ARCG) Technique. The above overall design is implemented in 250-nm CMOS design of the TANNER-EDA tool, consuming 1.74-mW power at 60[Formula: see text]MS/s. The proposed structure has an INL and a DNL, respectively, of +0.18/[Formula: see text] LSB and +0.11/[Formula: see text]0.05 LSB.

2021 ◽  
Author(s):  
Prathiba G ◽  
Shanthi M

Abstract This paper presents an analysis of Reversible Switching Capacitive Digital to Analog converter (RSC-DAC) based low power Successive Approximation Register Analog to Digital Converter (SAR-ADC).The proposed structure involves, the QVDC (Quantum Voltage Differential Comparator) constructed using Simple Transconductance Amplifier (STA) technique , the RSC-DAC switching energy reduced by 93% contrast to the standard Charge Redistribution Switching Capacitive DAC (CRSC-DAC) method, and the Successive Approximation Register(SAR) control logic is designed with D-FF based shift register. The QVDC comparator allows very small voltage comparison, and consumes low power and area effective. The linearity parameters such as Integral Nonlinearity, Differential Nonlinearity and parasitic effect of the capacitor of the RSC-DAC is analyzed and improved by the new approach is named as Adaptive Random Code Generation (ARCG) Technique. The above overall design is implemented by TANNER-EDA tool in 250nm CMOS technology, consumes 1.74mW power at 60MS/s. The INL and DNL of the proposed structure is +0.18/-0.12 LSB and +0.11/-0.05 LSB respectively.


Author(s):  
Mrs. Lakshmidevi TR ◽  
Mr. K N Jeevan Reddy ◽  
Mr. Ashrith Rao ◽  
Mr. Dhanush Kashyap S ◽  
Ms. Chandini K

In recent years, we have come across a growing need for the design of low power, long battery life Successive Approximation Register (SAR) Analog-to-Digital Converters (ADC). ADCs are the major component of all the systems which need to process an analogue signal obtained from measuring real world parameters and hence they need to be efficient enough depending on the application and power constraint of the device. Speed is also an important parameter as it is used in many real time applications. The basic components of the SAR ADC can be implemented using circuits of various logics available for the logic gates, adders, comparators utilised in it. This paper presents the working of 4-bit successive approximation register analog-to-digital converters (SAR ADC) in three different logics namely, Complementary Metal Oxide Semiconductors (CMOS), Transmission Gates (TG), and Double Pass Transistors (DPL) logics, which were used in the basic components of each major block of the ADC. The aim of this paper here is to compare the various parameters such as area, power consumption and delay between the three different technologies chosen above. The SAR ADCs were implemented for this purpose in 90nm Technology using the Cadence Virtuoso Design Tool building schematics and layouts for the same and calculating the various parameters required for the above-mentioned comparison.


2020 ◽  
Vol 15 (4) ◽  
pp. 478-486
Author(s):  
Sheng-Biao An ◽  
Li-Xin Zhao ◽  
Shi-Cong Yang ◽  
Tao An ◽  
Rui-Xia Yang

This paper presents a charge redistributed successive approximation register analog-to-digital converter (SAR ADC). Compared with the traditional Digital-Analog Convertor (DAC), the power consumption of the DAC scheme is reduced by 90%, the area is reduced by 60%. The test chip fabricated in 180 nm Complementary Metal Oxide Semiconductor (CMOS) occupied an active area of 0.12 mm 2 . At 10 MS/s, a signal-to-noise and distortion ratio (SNDR) of 57.70 dB and a spurious-free dynamic range (SFDR) of 55.63 dB are measured with 1.68 Vpp differential-mode input signal. The total power consumption is 690 μW corresponding to 67 fJ/conversion step figure of merit.


2014 ◽  
Vol 23 (02) ◽  
pp. 1450026 ◽  
Author(s):  
REZA INANLOU ◽  
MOHAMMAD YAVARI

In this paper, a 10-bit 0.5 V 100 kS/s successive approximation register (SAR) analog-to-digital converter (ADC) with a new fully dynamic rail-to-rail comparator is presented. The proposed comparator enhances the input signal range to the rail-to-rail mode, and hence, improves the signal-to-noise ratio (SNR) of the ADC in low supply voltages. The effect of the latch offset voltage is reduced by providing a higher voltage gain in the regenerative latch. To reduce the ADC power consumption further, the binary-weighted capacitive array with an attenuation capacitor (BWA) is employed as the digital-to-analog converter (DAC) in this design. The ADC is designed and simulated in a 90 nm CMOS process with a single 0.5 V power supply. Spectre simulation results show that the average power consumption of the proposed ADC is about 400 nW and the peak signal-to-noise plus distortion ratio (SNDR) is 56 dB. By considering 10% increase in total ADC power consumption due to the parasitics and a loss of 0.22 LSB in ENOB due to the DAC capacitors mismatch, the achieved figure of merit (FoM) is 11.4 fJ/conversion-step.


2013 ◽  
Vol 11 ◽  
pp. 227-230
Author(s):  
J. Bialek ◽  
A. Wickmann ◽  
F. Ohnhaeuser ◽  
G. Fischer ◽  
R. Weigel ◽  
...  

Abstract. Successive approximation register (SAR) analog-to-digital Converters (ADC) are based on a capacitive digital-to-analog converter (CDAC) (McCreary and Gray, 1975). The capacitor mismatch in the capacitor array of the CDAC impacts the differential non-linearity (DNL) of the ADC directly. In order to achieve a transfer function without missing codes, trimming of the capacitor array becomes necessary for SAR ADCs with a resolution of more than 12 bit. This article introduces a novel digital approach for trimming. DNL measurements of an 18 bit SAR ADC show that digital trimming allows the same performance as analog trimming. Digital trimming however reduces the power consumption of the ADC, the die size and the required time for the production test.


2021 ◽  
Author(s):  
Daniel Junehee Lee

file:///C:/Users/MWF/Downloads/Lee, Daniel Junehee.The 8-bit digital-to-time converter (DTC) to be used for a time-mode successive-approximation register analog-to-digital converter (SAR ADC) with a minimum power consumption and silicon area is presented. The architecture and the drawbacks of a conventional voltage-mode SAR ADC are discussed. The principle of time-mode circuits and benefits of their applications to mixed-signal circuits are explained. The architecture of a time-mode SAR ADC is presented. The need for an area and power-efficient DTC to be used for a time-mode SAR ADC is discussed. The principle of a DTC is explained and prior works on a DTC are reviewed. The principle of a phase interpolator (PI), to be used for a DTC, is explained and prior works on digital PIs are reviewed. The design of the proposed DTC is presented. Each block of the proposed DTC is explained using schematic and layout views. Optimal slope of the input of the PI and the condition for linear phase interpolation are investigated. Simulation results of the proposed DTC designed in TSMC 65 nm 1.0 V CMOS technology are provided. According to simulation results with BSIM4.4 device models only, the time resolution of 0.33 ps, a maximum operation frequency of 2.53 G Hz, the power consumption of 1.38 mW, and peak differential nonlinearity (DNL) and integral nonlinearity (INL) less than 0.14 least significant bit (LSB) and 0.49 LSB, respectively, for a nominal process (TT) and a temperature condition (27 C°) are achieved.


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