A Linearity Improved 10-bit 120-MS/s 1.5 mW SAR ADC with High-Speed and Low-Noise Dynamic Comparator Technique

2019 ◽  
Vol 29 (06) ◽  
pp. 2050084
Author(s):  
Daiguo Xu ◽  
Hequan Jiang ◽  
Dongbin Fu ◽  
Xiaoquan Yu ◽  
Shiliu Xu ◽  
...  
Keyword(s):  
High Speed ◽  
Cmos Technology ◽  
Low Noise ◽  
Sar Adc ◽  
Dynamic Comparator ◽  
Analog To Digital ◽  
Input Noise ◽  
Clock Feedthrough ◽  
Threshold Voltages ◽  
Coupled Technique

This paper presents a linearity improved 10-bit 120-MS/s successive approximation register (SAR) analog-to-digital converter (ADC) with high-speed and low-noise dynamic comparator. A gate cross-coupled technique is introduced in boost sampling switch, the clock feedthrough effect is compensated without extra auxiliary switch and the linearity of sampling switch is enhanced. Further, substrate voltage boost technique is proposed, the absolute values of threshold voltage and equivalent impedances of MOSFETs are both depressed. Consequently, the delay of comparator is also reduced. Moreover, the reduction of threshold voltages for input MOSFETs could bring higher transconductance and lower equivalent input noise. To demonstrate the proposed techniques, a design of SAR ADC is fabricated in 65-nm CMOS technology, consuming 1.5[Formula: see text]mW from 1[Formula: see text]V power supply with a SNDR [Formula: see text][Formula: see text]dB and SFDR [Formula: see text][Formula: see text]dB. The proposed ADC core occupies an active area of 0.021[Formula: see text]mm2, and the corresponding FoM is 24.4 fJ/conversion-step with Nyquist frequency.

A System-Level Correction SAR ADC with Noise-Tolerant Technique

2018 ◽  
Vol 27 (13) ◽  
pp. 1850202
Author(s):  
Daiguo Xu ◽  
Kaikai Xu ◽  
Shiliu Xu ◽  
Lu Liu ◽  
Tao Liu
Keyword(s):  
High Speed ◽  
Cmos Technology ◽  
Sar Adc ◽  
System Level ◽  
Small Noise ◽  
Dynamic Comparator ◽  
Analog To Digital ◽  
The Core ◽  
Measurement Results ◽  
Noise Tolerant

A system-level correction successive approximation register analog-to-digital converter (SAR ADC) with regulated comparator of noise-tolerant technique is proposed. First, a substrate voltage boost technique is provided to improve the linearity and speed of sampling switch. Secondly, the proposed SAR ADC provides a comparator of noise regulation without redundant comparison cycle. The proposed comparator would be regulated in high-speed large noise state in large input differential signals. In the condition of small input differential signals, the comparator would be adjusted to low-speed small noise state. Furthermore, a high-speed low-power technique is proposed to optimize the performance of dynamic comparator. Additionally, a fast SAR logic structure is provided to increase the conversion speed of SAR ADC. To demonstrate the proposed techniques, a design example of SAR ADC is fabricated in 65[Formula: see text]nm CMOS technology. The SAR ADC is able to tolerate about 1.1 LSB noise errors in post-simulation with the operation state regulated automatically. The core occupies an active area of only 0.025[Formula: see text]mm2 and consumes 1.5[Formula: see text]mW. Measurement results achieve SFDR [Formula: see text][Formula: see text]dB and SNDR [Formula: see text][Formula: see text]dB, resulting in the FOM of 21.6[Formula: see text]fJ per conversion step.

scholarly journals A 2.6 GS/s 8-Bit Time-Interleaved SAR ADC in 55 nm CMOS Technology

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 305 ◽  
Author(s):  
Dong Wang ◽  
Xiaoge Zhu ◽  
Xuan Guo ◽  
Jian Luan ◽  
Lei Zhou ◽  
...  
Keyword(s):  
High Speed ◽  
Complementary Metal Oxide Semiconductor ◽  
Cmos Technology ◽  
Sar Adc ◽  
Oxide Semiconductor ◽  
Power Measurement ◽  
Cmos Process ◽  
Analog To Digital ◽  
Full Speed ◽  
Time Interleaved

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.

A Noise Reduction 12-bit 125-MSPS SAR ADC with Modified Asynchronous Logic Regulation Technique

2020 ◽  
pp. 2150040
Author(s):  
Daiguo Xu ◽  
Han Yang ◽  
Xing Sheng ◽  
Ting Sun ◽  
Guangbing Chen ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Feedback Loop ◽  
Cmos Technology ◽  
Sar Adc ◽  
Dynamic Comparator ◽  
Digital To Analog Converter ◽  
Analog To Digital ◽  
Asynchronous Logic ◽  
Analog Converter ◽  
Nyquist Rate

This paper presents noise reduction and modified asynchronous logic regulation techniques used in successive approximation register (SAR) analog-to-digital converter (ADC). With a transconductance enhanced structure, noise reduction is provided in the dynamic comparator. The input referred noise of the proposed comparator is about 165[Formula: see text][Formula: see text]V rms at 60∘C (typical corner). An enhanced-positive-feedback loop is introduced to reduce the regeneration delay of the comparator. In addition, a modified asynchronous logic regulation technique is exhibited, a clock with adaptable delay is driving the comparator in approximation phase. Consequently, the settling accuracy of DAC (Digital-to-Analog Converter) is enough and the conversion speed of SAR ADC is increased without any redundant cycles. To demonstrate the proposed techniques, a design of SAR ADC is fabricated in 65-nm CMOS technology, consuming 4[Formula: see text]mW from 1.2[Formula: see text]V power supply with a [Formula: see text][Formula: see text]dB and [Formula: see text][Formula: see text]dB. The proposed ADC core occupies an active area of 0.048[Formula: see text]mm2, and the corresponding FoM is 27.2[Formula: see text]fJ/conversion-step at Nyquist rate.

scholarly journals A 12-bit 30 MS/s Successive Approximation-Register Analog-to-Digital Converter with Foreground Digital Calibration Algorithm

Symmetry ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 165
Author(s):  
Shouping Li ◽  
Yang Guo ◽  
Jianjun Chen ◽  
Bin Liang
Keyword(s):  
Successive Approximation ◽  
High Speed ◽  
Low Noise ◽  
Digital Calibration ◽  
Cmos Process ◽  
Analog To Digital Converter ◽  
Digital Converter ◽  
Dynamic Comparator ◽  
Analog To Digital ◽  
Calibration Algorithm

This paper presents a foreground digital calibration algorithm based on a dynamic comparator that aims to reduce comparator offset and capacitor mismatch, as well as improve the performance of the successive approximation analog-to-digital converter (SARADC). The dynamic comparator is designed with two preamplifiers and one latch to facilitate high speed, high precision, and low noise. The foreground digital calibration algorithm provides high speed with minimal area consumption. This design is implemented on a 12-bit 30 MS/s SARADC with a standard 0.13 μm Complementary Metal Oxide Semiconductor (CMOS) process. The simulation Nyquist 68.56 dB signal-to-noise-and-distortion ratio (SNDR) and 84.45 dBc spurious free dynamic range (SFDR) at 30 MS/s, differential nonlinearity (DNL) and integral nonlinearity (INL) are within 0.64 Least Significant Bits (LSB) and 1.3 LSB, respectively. The ADC achieves an effective number of bits (ENOB) of 11.08 and a figure-of-merit (FoM) of 39.45 fJ/conv.-step.

A Low-Noise Dynamic Comparator with Offset Calibration for CMOS Image Sensor Architecture

2018 ◽  
Vol 28 (02) ◽  
pp. 1950022
Author(s):  
Arumugam Sathishkumar ◽  
Siddhan Saravanan
Keyword(s):  
High Speed ◽  
Cmos Image Sensor ◽  
Image Sensor ◽  
Low Noise ◽  
Clock Frequency ◽  
Dynamic Comparator ◽  
Analog To Digital ◽  
Input Capacitance ◽  
Simulation Results ◽  
Output Swing

A low-noise, high-speed, low-input-capacitance switched dynamic comparator (SDC) CMOS image sensor architecture is presented in this paper. The comparator design occupying less area and consuming lesser power is suitable for bank of comparators in CMOS image readouts. The proposed dynamic comparator eliminates the stacking issue related to the conventional comparator and reduces the offset noise further. The need for low-noise, low-power, area-efficient and high-speed flash analog-to-digital converters (ADCs) in many applications today motivated us to design a comparator for ADC. The rail-to-rail output swing is also improved. The input capacitance is reduced by using shared first-stage technique. The comparator is designed with constant [Formula: see text]/[Formula: see text] biasing to suppress the environmental drift. The simulation results from 45-nm and 65-nm CMOS technologies confirm the analysis results. It is shown that in the proposed dynamic comparator both the power consumption and delay time are significantly reduced. The maximum clock frequency of the proposed comparator can be increased to 3.5[Formula: see text]GHz and 2.2[Formula: see text]GHz at supply voltages of 1[Formula: see text]V and 0.6[Formula: see text]V, respectively. Simulations are carried out using predictive technology models for 45[Formula: see text]nm and 65[Formula: see text]nm in HSPICE.

scholarly journals A 14-bit High Speed 125MS/s Low Power SAR ADC using Dual Split Capacitor DAC Architecture in 90nm CMOS Technology

2021 ◽  
Vol 15 ◽  
pp. 556-568
Author(s):  
Chaya Shetty ◽  
M. Nagabushanam ◽  
Venkatesh Nuthan Prasad
Keyword(s):  
High Speed ◽  
Signal To Noise Ratio ◽  
Sampling Rate ◽  
Cmos Technology ◽  
Sar Adc ◽  
Cmos Process ◽  
Digital To Analog Converter ◽  
Additional Advantage ◽  
Analog To Digital ◽  
Split Capacitor

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.

ANALYSIS OF POWER CONSUMPTION SAR-ADC DYNAMIC COMPARATOR

2016 ◽  
Vol 78 (5-9) ◽  
Author(s):  
Julie R. Rusli ◽  
Noor Shelida Salleh ◽  
Masnita M. Isa ◽  
KY Tan ◽  
Suhaidi Shafie
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
Cmos Technology ◽  
Sar Adc ◽  
Dynamic Comparator ◽  
Ultra Low Power ◽  
Analog To Digital ◽  
Regeneration Time ◽  
Dynamic Comparators ◽  
Reset Time

Due to the high demand of ultra-low power in digital application, the needs of energy efficient analog-to-digital converter (ADC) are really essential. The comparator being an important part of successive approximation register (SAR)-ADC needs to have optimum performance under low power condition. This paper presents the comparison on power consumption together with the output performance flow power SAR-ADC dynamic comparators from three different design proposed by previous researchers. The three circuits is simulated and compared in terms of power consumption, regeneration time, reset time and output transient.  The simulation is using Cadence Spectre and setup with 0.18µm CMOS technology, VDD at 0.8V and clock speed 2 at MHz.  The analysis results obtained provides the lowest voltage input different (ΔVin) possible for double tail dynamic comparator using 0.18µm CMOS technology while adhering to the 45 corner process requirement.  The results can be used as references for further design of ultra-low power dynamic comparator.

Design and Implementation of SAR-ADC for Medical Electronic Applications

2018 ◽  
Vol 8 (5) ◽  
pp. 55
Author(s):  
L V Santosh Kumar Y
Keyword(s):  
Communication Systems ◽  
High Speed ◽  
Printed Circuit Board ◽  
Health Care Systems ◽  
Cmos Technology ◽  
Sar Adc ◽  
Circuit Board ◽  
Analog To Digital ◽  
Ring Counter ◽  
Care Systems

in today’s advance electronic and communication systems the role of high accuracy analog to digital converters are of great importance. Nowadays, a larger percentage of mixed-signal applications requires for health care systems. Also the speed of the chosen ADC design matters a lot as we are connected with the real world signals. SAR based ADC will provides us a better solution for various analog to digital systems. It is an essential device whenever data from the analog world, through sensors or transducers, should be digitally processed or when transmitting data between chips through either long-range wireless links or high-speed transmission between chips on the same printed circuit board. The paper projects up down and ring counter as a logic for successive approximation register (SAR logic for a ADC that is one of the best suited for low power. Here the resolution is of 4-bit and a power consumption of few milli watts. SAR ADC is implemented in 45 nm nano-meter scaling technology CMOS technology with a power supply of 0.5v by maintaining 4:1 w/l ratio.

scholarly journals An 11 GHz Dual-Sided Self-Calibrating Dynamic Comparator in 28 nm CMOS

Electronics ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 13 ◽  
Author(s):  
Athanasios Ramkaj ◽  
Maarten Strackx ◽  
Michiel Steyaert ◽  
Filip Tavernier
Keyword(s):  
High Resolution ◽  
High Speed ◽  
State Of The Art ◽  
Low Noise ◽  
Dynamic Comparator ◽  
Analog To Digital ◽  
Ideal Candidate ◽  
Offset Voltage ◽  
Multi Stage ◽  
28 Nm

This paper demonstrates a high-speed, low-noise dynamic comparator, employing self-calibration. The proposed dual-sided, fully-dynamic offset calibration is able to reduce the input-referred offset voltage by a factor of ten compared to the uncalibrated value without any speed or noise penalty and with less than 5% power overhead. Moreover, the implemented multi-stage topology significantly advances the state-of-the-art comparator performance, achieving the highest reported operating frequency, as well as the lowest delay slope and sensitivity to supply and common mode variations compared to existing works, with similar energy/comparison. This makes the proposed self-calibrating comparator an ideal candidate for high resolution (>10 b) multi-GHz Analog-to-Digital Converters (ADCs). The 28 nm bulk CMOS prototype measures an input-referred noise and calibrated offset of 0.82 mV and 0.99 mV, respectively clocked at 11 GHz, consuming only 0.89 mW from a 1 V supply, for an area of 0.00054 mm2, including calibration.

An Encoder Used in an Ultra High-Speed Folding and Interpolating ADC

2014 ◽  
Vol 1049-1050 ◽  
pp. 687-690
Author(s):  
Yu Han Gao ◽  
Ru Zhang Li ◽  
Dong Bing Fu ◽  
Yong Lu Wang ◽  
Zheng Ping Zhang
Keyword(s):  
High Speed ◽  
Binary Code ◽  
Sampling Rate ◽  
Gray Code ◽  
Cmos Technology ◽  
Careful Consideration ◽  
Analog To Digital ◽  
Interleaved Adc ◽  
Time Interleaved ◽  
Error Suppression

High speed encoder is the key element of high speed analog-to-digital converter (ADC). Therefor the type of encoder, the type of code, bubble error suppression and bit synchronization must be taken into careful consideration especially for folding and interpolating ADC. To reduce the bubble error which may resulted from the circuit niose, comparator metastability and other interference, the output of quantizer is first encoded with gray code and then converted to binary code. This high speed encoder is verified in the whole time-interleaved ADC with 0.18 Bi-CMOS technology, the whole ADC can achieve a SNR of 45 dB at the sampling rate of 5GHz and input frequency of 495MHz, meanwhile a bit error rate (BER) of less than 10-16 is ensured by this design.

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