scholarly journals A 28 nm CMOS 10 bit 100 MS/s Asynchronous SAR ADC with Low-Power Switching Procedure and Timing-Protection Scheme

Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2856
Author(s):  
Fang Tang ◽  
Qiyun Ma ◽  
Zhou Shu ◽  
Yuanjin Zheng ◽  
Amine Bermak
Keyword(s):  
Dynamic Range ◽  
Supply Voltage ◽  
Sar Adc ◽  
Cmos Process ◽  
Power Switching ◽  
Analog To Digital ◽  
Protection Scheme ◽  
Area Efficiency ◽  
Asynchronous Sar ◽  
28 Nm

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.

scholarly journals Current Input Pixel-Level ADC with High SNR and Wide Dynamic Range for a Microbolometer

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2354
Author(s):  
Jeongho Lee ◽  
Ilku Nam ◽  
DooHyung Woo
Keyword(s):  
Dynamic Range ◽  
Supply Voltage ◽  
Signal To Noise Ratio ◽  
Integration Time ◽  
Cmos Process ◽  
Readout Circuit ◽  
Power Supply Voltage ◽  
Analog To Digital ◽  
Current Input ◽  
Cell Circuit

A readout circuit incorporating a pixel-level analog-to-digital converter (ADC) is studied for two-dimensional medium wavelength infrared microbolometer arrays. The signal-to-noise ratio (SNR) and charge handling capacity of the unit cell circuit are improved by using the current input pixel-level ADC. The charge handling capacity of the integrator is appropriately extended to maximize the integration time regardless of the magnitude of the input current and low power supply voltage. The readout circuit was fabricated using a 0.35-μm 2-poly 4-metal CMOS process for a 640 × 512 array with a pixel size of 40 μm × 40 μm. The peak SNR and dynamic range are 77.1 and 80.1 dB, respectively, with a power consumption of 0.62 μW per pixel.

scholarly journals A 12-bit 40-MS/s SAR ADC with Calibration-Less Switched Capacitive Reference Driver

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1854
Author(s):  
Hyungyu Ju ◽  
Sewon Lee ◽  
Minjae Lee
Keyword(s):  
Dynamic Range ◽  
Supply Voltage ◽  
Voltage Drop ◽  
Sar Adc ◽  
Cmos Process ◽  
Nyquist Frequency ◽  
Digital To Analog Converter ◽  
Spurious Free Dynamic Range ◽  
Analog Converter ◽  
Free Dynamic

This paper presents a switched capacitive reference driver (SCRD) with a low-energy switching scheme. In order to reduce the performance degradation resulting from a signal-dependent voltage drop in a capacitive reference driver (CRD) without increasing the capacitance (CREF) of a CRD, the proposed SCRD utilizes the CRD for LSB conversion cycles. In MSB conversion cycles, a supply voltage is used as a reference voltage to save on area and power consumption. As such, the proposed SCRD significantly relaxes the required CREF, and does not necessitate bit weight calibration or compensation requiring an auxiliary capacitor-based digital-to-analog converter (CDAC). To evaluate the proposed SCRD, a prototype 12-bit 40-MS/s SAR ADC is fabricated in a 65 nm CMOS process. With near Nyquist frequency, the measured spurious-free dynamic range (SFDR) of the SAR ADC with the SCRD is 80.6 dB, which is about a 16 dB improvement from the SFDR of a SAR ADC with a CRD only.

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
Keyword(s):  
Calibration Method ◽  
Sar Adc ◽  
Calibration Error ◽  
Cmos Process ◽  
Analog To Digital ◽  
Significant Performance ◽  
Performance Deterioration ◽  
Conventional Structure ◽  
Split Capacitor ◽  
Simulation Results

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.

scholarly journals A 3GSps 12-bit Four-Channel Time-Interleaved Pipelined ADC in 40 nm CMOS Process

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1551 ◽  
Author(s):  
Jianwen Li ◽  
Xuan Guo ◽  
Jian Luan ◽  
Danyu Wu ◽  
Lei Zhou ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Cmos Process ◽  
Pipelined Adc ◽  
Least Significant Bit ◽  
Analog To Digital ◽  
Capacitor Mismatch ◽  
Gain Error ◽  
Spurious Free Dynamic Range ◽  
Time Interleaved ◽  
Free Dynamic

This paper presents a four-channel time-interleaved 3GSps 12-bit pipelined analog-to-digital converter (ADC). The combination of master clock sampling and delay-adjusting is adopted to remove the time skew due to channel mismatches. An early comparison scheme is used to minimize the non-overlapping time, where a custom-designed latch is developed to replace the typical non-overlapping clock generator. By using the dither capacitor to generate an equivalent direct current input, a zero-input-based calibration is developed to correct the capacitor mismatch and inter-stage gain error. Fabricated in a 40 nm CMOS process, the ADC achieves a signal-to-noise-and-distortion ratio (SNDR) of 57.8 dB and a spurious free dynamic range (SFDR) of 72 dB with a 23 MHz input tone. It can achieve an SNDR above 52.3 dB and an SFDR above 61.5 dB across the entire first Nyquist zone. The differential and integral nonlinearities are −0.93/+0.73 least significant bit (LSB) and −2.8/+4.3 LSB, respectively. The ADC consumes 450 mW powered at 1.8V, occupies an active area of 3 mm × 1.3 mm. The calculated Walden figure of merit reaches 0.44 pJ/step.

scholarly journals A Novel Highly Linear Voltage-To-Time Converter (VTC) Circuit for Time-Based Analog-To-Digital Converters (ADC) Using Body Biasing

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2033
Author(s):  
Ahmed Elgreatly ◽  
Ahmed Dessouki ◽  
Hassan Mostafa ◽  
Rania Abdalla ◽  
El-sayed El-Rabaie
Keyword(s):  
Power Consumption ◽  
Software Defined Radio ◽  
Dynamic Range ◽  
Supply Voltage ◽  
Cmos Technology ◽  
The Body ◽  
Analog To Digital Converters ◽  
Clock Frequency ◽  
Analog To Digital ◽  
Operation Speed

Time-based analog-to-digital converter is considered a crucial part in the design of software-defined radio receivers for its higher performance than other analog-to-digital converters in terms of operation speed, input dynamic range and power consumption. In this paper, two novel voltage-to-time converters are proposed at which the input voltage signal is connected to the body terminal of the starving transistor rather than its gate terminal. These novel converters exhibit better linearity, which is analytically proven in this paper. The maximum linearity error is reduced to 0.4%. In addition, the input dynamic range of these converters is increased to 800 mV for a supply voltage of 1.2 V by using industrial hardware-calibrated TSMC 65 nm CMOS technology. These novel designs consist of only a single inverter stage, which results in reducing the layout area and the power consumption. The overall power consumption is 18 μW for the first proposed circuit and 15 μW for the second proposed circuit. The novel converter circuits have a resolution of 5 bits and operate at a maximum clock frequency of 500 MHz.

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.

Area-Efficient Capacitor-Splitting Switching Scheme with a Nearly Constant Common-Mode Voltage for SAR ADCs

2019 ◽  
Vol 29 (10) ◽  
pp. 2020005
Author(s):  
Hao Wang ◽  
Wenming Xie ◽  
Zhixin Chen
Keyword(s):  
Dynamic Range ◽  
Supply Voltage ◽  
Sampling Rate ◽  
Cmos Technology ◽  
Switching Scheme ◽  
Common Mode ◽  
Analog To Digital ◽  
Common Mode Voltage ◽  
Switching Method ◽  
Area Efficient

A novel area-efficient switching scheme is proposed for the successive approximation register (SAR) analog-to-digital converters (ADCs). The capacitor-splitting structure, charge-average switching technique, and [Formula: see text] (equal to [Formula: see text]/4) are combined together and optimized to realize the proposed switching scheme. [Formula: see text] is only used in the last two bit cycles, which affects the ADC accuracy little and reduces capacitor area by half. It achieves a 98% less switching energy and an 87.5% less capacitor area compared with the conventional switching method. In addition, the DAC output common-mode voltage is approximately constant. Thus, the proposed switching method is a good tradeoff among power consumption, capacitor area, DAC output common-mode voltage, and ADC accuracy. The proposed SAR ADC is simulated in 0.18[Formula: see text][Formula: see text]m CMOS technology with a supply voltage of 0.6[Formula: see text]V and at a sampling rate of 20[Formula: see text]kS/s. The signal-to-noise-distortion ratio (SNDR) and spurious free dynamic range (SFDR) are 58.2 and 73.7[Formula: see text]dB, respectively. The effective number of bits (ENOB) is 9.4. It consumes 42[Formula: see text]nW, resulting in a figure-of-merit (FoM) of 3.11 fJ/conversion-step.

scholarly journals A Design of Low-Power 10-bit 1-MS/s Asynchronous SAR ADC for DSRC Application

Electronics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1100
Author(s):  
Deeksha Verma ◽  
Khuram Shehzad ◽  
Danial Khan ◽  
Sung Jin Kim ◽  
Young Gun Pu ◽  
...  
Keyword(s):  
Low Power ◽  
Sampling Rate ◽  
Complementary Metal Oxide Semiconductor ◽  
Sar Adc ◽  
Oxide Semiconductor ◽  
Digital To Analog Converter ◽  
Analog To Digital ◽  
Clock Generation ◽  
Analog Converter ◽  
Asynchronous Sar

A design of low-power 10-bit 1 MS/s asynchronous successive approximation register analog-to-digital converter (SAR ADC) is presented in this paper. To improve the linearity of the digital-to-analog converter (DAC) and energy efficiency, a common mode-based monotonic charge recovery (CMMC) switching technique is proposed. The proposed switching technique consumes only 63.75 CVREF2 switching energy, which is far less as compared to the conventional switching technique without dividing or adding additional switches. In addition, bootstrap switching is implemented to ensure enhanced linearity. To reduce the power consumption from the comparator, a dynamic latch comparator with a self-comparator clock generation circuit is implemented. The proposed prototype of the SAR ADC is implemented in a 55 nm CMOS (complementary metal-oxide-semiconductor) process. The proposed architecture achieves a figure of merit (FOM) of 17.4 fJ/conversion, signal-to-noise distortion ratio (SNDR) of 60.39 dB, and an effective number of bits (ENOB) of 9.74 bits with a sampling rate of 1 MS/s at measurement levels. The implemented SAR ADC consumes 14.8 µW power at 1 V power supply.

A ΣΔ MODULATOR USING GAIN-BOOST CLASS-C INVERTER FOR AUDIO APPLICATIONS

2013 ◽  
Vol 22 (10) ◽  
pp. 1340024
Author(s):  
HAO LUO ◽  
YAN HAN ◽  
RAY C. C. CHEUNG ◽  
TIANLIN CAO ◽  
XIAOPENG LIU ◽  
...  
Keyword(s):  
High Resolution ◽  
Dynamic Range ◽  
Supply Voltage ◽  
Cmos Process ◽  
Signal To Noise ◽  
Dc Gain ◽  
Micro Power ◽  
Class C ◽  
On Chip ◽  
Σδ Modulator

This paper provides an audio 2-1 cascaded ΣΔ modulator using a novel gain-boost class-C inverter. The gain-boost class-C inverter behaves as a subthreshold amplifier. By introducing a gain-boost module, the inverter DC-gain is increased from 48 dB to 67 dB. The gain-boost class-C inverter consumes 57 μW at 1.2-V supply, where the gain-boost module consumes only 3 μW. In addition, an on-chip body bias technique is introduced to compensate the process and supply voltage variations of the class-C inverter. The proposed inverter-based ΣΔ modulator chip is implemented in 0.13-μm CMOS process, and achieves 86-dB peak-signal to noise and distortion ratio (SNDR) and 90-dB dynamic range (DR) over 22.05-KHz bandwidth at 1.2-V supply consuming 360 μW, which demonstrates that the gain-boost class-C inverter is particularly suitable for micro-power high-resolution applications.

scholarly journals Modeling of High-Resolution Data Converter: Two-Step Pipelined-SAR ADC based on ISDM

Electronics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 137 ◽  
Author(s):  
Bo Gao ◽  
Xin Li ◽  
Jie Sun ◽  
Jianhui Wu
Keyword(s):  
High Resolution ◽  
Low Noise ◽  
Sar Adc ◽  
Total Power ◽  
Cmos Process ◽  
Analog To Digital Converter ◽  
Digital Converter ◽  
Signal To Noise ◽  
Analog To Digital ◽  
High Bandwidth

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.

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