Study of Split Capacitor DAC Mismatch and Calibration in SAR-ADC

2016 ◽  
Vol 26 (01) ◽  
pp. 1750003
Author(s):  
Yun Zhang ◽  
Yiqiang Zhao ◽  
Peng Dai

Mismatch and parasitic effects of bridge capacitors in successive-approximation-register analog-to-digital converter’s (SAR-ADC) split capacitor digital-to-analog conversion (DAC) cause a significant performance deterioration. This paper presents a nonlinearity analysis based on an analytical model, and a modified calibration method utilizing a pre-bias bridge capacitor is accordingly proposed. The proposed method, which uses three-segment split capacitor DAC structure, can effectively eliminate over-calibration error caused by conventional structure. To verify the technique, a 14-bit SAR-ADC has been designed in 0.35-[Formula: see text]m 2P4M CMOS process with the PIP capacitor, and the simulation results show the method can further improve ADC performance.

2014 ◽  
Vol 23 (05) ◽  
pp. 1450057
Author(s):  
SAHAR SARAFI ◽  
KHEYROLLAH HADIDI ◽  
EBRAHIM ABBASPOUR ◽  
ABU KHARI BIN AAIN ◽  
JAVAD ABBASZADEH

This paper presents an analog-to-digital converter (ADC), using pipelined successive approximation register (SAR) architecture. The structure which is a combination of SAR-ADC and pipelined ADC benefits from each of their advantages. A new synchronization method is proposed to improve the pipelined SAR-ADC's speed. The proposed method reduces the total conversion without limiting the ADC performance. To evaluate the proposed method a 10-bit 100 MS/s is designed in 0.5 μm CMOS process technology. According to the obtained simulation results, the designed ADC digitizes a 9-MHz input with 54.19 dB SNDR while consuming 57.3 mw from a 5-V supply.


Author(s):  
Chaya Shetty ◽  
M. Nagabushanam ◽  
Venkatesh Nuthan Prasad

The proposed work presents a High speed 14-bit 125MS/s successive-approximation-register asynchronous analog-to-digital-converter (SAR-ADC). A novel-based Dual-Split-Array-Three-Section (DSATS) capacitor DAC (DSATS-CDAC) is employed to increase the linearity and energy efficiency of the digital-to-analog converter (DAC), additional advantage of this work is that, the area is reduced by 59.76% of conventional design. The proposed switching technique of the (DSATS-CDAC) consumes less switching energy. Additionally, bootstrap switching is employed to ensure improved linearity and reduced power consumption.in order to enhance the speed of operation and increase the precision a preamplifier latch based comparator is implemented with the delay of 250ps. The proposed SAR-ADC prototype is implemented in a 90nm CMOS process and consumes a power of 42.8mW at 1V operating supply. The proposed design achieves a figure of merit (FOM) of 37.43 fJ/conversion-step, signal-to-noise-ratio (SNR) of 81 dB, and an effective-number-of-bits (ENOB) of 13.16 bits with a sampling rate of 125MS/s.


Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 305 ◽  
Author(s):  
Dong Wang ◽  
Xiaoge Zhu ◽  
Xuan Guo ◽  
Jian Luan ◽  
Lei Zhou ◽  
...  

This paper presents an eight-channel time-interleaved (TI) 2.6 GS/s 8-bit successive approximation register (SAR) analog-to-digital converter (ADC) prototype in a 55-nm complementary metal-oxide-semiconductor (CMOS) process. The channel-selection-embedded bootstrap switch is adopted to perform sampling times synchronization using the full-speed master clock to suppress the time skew between channels. Based on the segmented pre-quantization and bypass switching scheme, double alternate comparators clocked asynchronously with background offset calibration are utilized in sub-channel SAR ADC to achieve high speed and low power. Measurement results show that the signal-to-noise-and-distortion ratio (SNDR) of the ADC is above 38.2 dB up to 500 MHz input frequency and above 31.8 dB across the entire first Nyquist zone. The differential non-linearity (DNL) and integral non-linearity (INL) are +0.93/−0.85 LSB and +0.71/−0.91 LSB, respectively. The ADC consumes 60 mW from a 1.2 V supply, occupies an area of 400 μm × 550 μm, and exhibits a figure-of-merit (FoM) of 348 fJ/conversion-step.


2015 ◽  
Vol 46 (6) ◽  
pp. 431-438 ◽  
Author(s):  
Peng Dai ◽  
Yiqiang Zhao ◽  
Yun Sheng ◽  
Yun Zhang

Electronics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 137 ◽  
Author(s):  
Bo Gao ◽  
Xin Li ◽  
Jie Sun ◽  
Jianhui Wu

The features of high-resolution and high-bandwidth are in an increasing demand considering to the wide range application fields based on high performance data converters. In this paper, a modeling of high-resolution hybrid analog-to-digital converter (ADC) is proposed to meet those requirements, and a 16-bit two-step pipelined successive approximation register (SAR) analog-to-digital converter (ADC) with first-order continuous-time incremental sigma-delta modulator (ISDM) assisted is presented to verify this modeling. The combination of high-bandwidth two-step pipelined-SAR ADC with low noise ISDM and background comparator offset calibration can achieve higher signal-to-noise ratio (SNR) without sacrificing the speed and plenty of hardware. The usage of a sub-ranging scheme consists of a coarse SAR ADC followed by an fine ISDM, can not only provide better suppression of the noise added in 2nd stage during conversion but also alleviate the demands of comparator’s resolution in both stages for a given power budget, compared with a conventional Pipelined-SAR ADC. At 1.2 V/1.8 V supply, 33.3 MS/s and 16 MHz input sinusoidal signal in the 40 nm complementary metal oxide semiconductor (CMOS) process, the post-layout simulation results show that the proposed hybrid ADC achieves a signal-to-noise distortion ratio (SNDR) and a spurious free dynamic range (SFDR) of 86.3 dB and 102.5 dBc respectively with a total power consumption of 19.2 mW.


2013 ◽  
Vol 22 (04) ◽  
pp. 1350026 ◽  
Author(s):  
ZHANGMING ZHU ◽  
YU XIAO ◽  
LIANG LIANG ◽  
LIANXI LIU ◽  
YINTANG YANG

Based on TSMC 0.18 μm 1.8 V CMOS process, a low power 10-bit 200 KS/s successive approximation register (SAR) analog-to-digital (ADC) is realized. This paper mainly considers the improvement of linearity and the optimization of power consumption. And a novel switching sequence is proposed which allows both to achieve a better compromise. Moreover, the fully dynamic comparator, which consumes no static power, and the optimization of SAR control logic, further reduce power consumption. The simulation results show that at 1.0 V supply and 200 KS/s, the ADC achieves an signal-to-noise and distortion-ration (SNDR) of 59.78 dB and consumes 3.03 μW, resulting in a figure-of-merit (FOM) of 19.0 fJ/conversion-step. The ADC core occupies an active area of only 260 × 220 μm2.


Nowadays, there is an increasing demand for Successive Approximation Register (SAR) based Analog to Digital Converter (ADC) in long battery applications like medical application, Sensors and many more. In this paper DAC circuit is designed using multiple capacitor and Multiple MUX for switching. A split based capacitor is used for boosting the speed of the architecture. In split based DAC no common mode voltage required and dynamic offset can be removed as well. In this work, 12-Bit DAC and encoder is designed using 2 Transistor MUX and 18 Transistor Full adders (12B-2TM-18TFA). 2T and 18T is used to design the MUX and FA. This entire architecture is implemented in Cadence Virtuoso 45nm CMOS technology. Simultaneously, 10B-12TM-36TFA architecture also implemented in this paper. The performance parameters like area, power, and delay, current is evaluated for both architectures. Result showed that 12B-2TM-18TFA architecture consumed less area, less power, less delay, and less current compared to 10B-12TM-36TFA.


2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Chengying Chen ◽  
Liming Chen ◽  
Jun Yang

A mixed-signal programmable Time-Division Power-On-Reset (TD-POR) circuit based on 8-bit Successive Approximation Analog-to-Digital Converter (SAR ADC) for accurate control in low-power hearing-aid System on Chip (SoC) is presented in this paper. The end-of-converter (EOC) signal of SAR ADC is used as the mode-change signal so that the circuit can detect the battery voltage and volume voltage alternately. And the TD-POR circuit also has brown-out reset (BOR) detection capability. Through digital logic circuit, the POR, BOR threshold, and delay time can be adjusted according to the system requirement. The circuit is implemented in SMIC 0.13 μm 1P8M CMOS process. The measurement results show that, in 1 V power supply, the POR, BOR, and volume control function are accomplished. The detection resolution is the best among previous work. With 120 Hz input signal and 15 kHz clock, the ADC shows that Signal to Noise plus Distortion Ratio (SNDR) is 46.5 dB and Effective Number Of Bits (ENOB) is 7.43 bits. Total circuit power consumption is only 86 μw for low-power application.


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.


Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2856
Author(s):  
Fang Tang ◽  
Qiyun Ma ◽  
Zhou Shu ◽  
Yuanjin Zheng ◽  
Amine Bermak

This paper presents a 10 bit 100 MS/s asynchronous successive approximation register (SAR) analog-to-digital converter (ADC) without calibration for industrial control system (ICS) applications. Several techniques are adopted in the proposed switching procedure to achieve better linearity, power and area efficiency. A single-side-fixed technique is utilized to reduce the number of capacitors; a parallel split capacitor array in combination with a partially thermometer coded technique can minimize the switching energy, improve speed, and decrease differential non-linearity (DNL). In addition, a compact timing-protection scheme is proposed to ensure the stability of the asynchronous SAR ADC. The proposed ADC is fabricated in a 28 nm CMOS process with an active area of 0.026 mm2. At 100 MS/s, the ADC achieves a signal-to-noise-and-distortion ratio (SNDR) of 51.54 dB and a spurious free dynamic range (SFDR) of 55.12 dB with the Nyquist input. The measured DNL and integral non-linearity (INL) without calibration are +0.37/−0.44 and +0.48/−0.63 LSB, respectively. The power consumption is 1.1 mW with a supply voltage of 0.9 V, leading to a figure of merit (FoM) of 35.6 fJ/conversion-step.


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