scholarly journals Delta-Sigma Modulator with Relaxed Feedback Timing for High Speed Applications

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1138
Author(s):  
Youngho Jung ◽  
Jooyoung Jeon

In this paper, a ΔΣ analog-to-digital converter (ADC) was designed and measured for broadband and high-resolution applications by applying the simple circuit technique to alleviate the feedback timing of input feed-forward architecture. With the proposed technique, a low-speed comparator and dynamic element matching (DEM) logic can be applied even for high-speed implementation, which helps to decrease power dissipation. Two prototypes using slightly different input branch topologies were fabricated with a 0.18 um 2-poly and 4-metal CMOS process, and measured to demonstrate the effectiveness of the proposed circuit technique. The sampling capacitor and feedback DAC capacitors were separated in prototype A, while they were shared in prototype B. The prototypes achieved 81.2 dB and 72.4 dB of SNDR in a 2.1 MHz signal band, respectively.

2019 ◽  
Vol 8 (4) ◽  
pp. 4053-4057

This paper describes the design and implementation of open loop sample and hold circuit using bootstrap technique, which can be used as front end sampling circuit for high speed analog-to-digital converters. Different design criteria viz. speed, power, resolution, linearity, noise and harmonic analysis have been dealt with. Both theoretical analysis and simulation results are carried out. The bootstrap circuit is designed and then compared in a 0.18μm and 0.35μm CMOS process. It is observed that signal to noise and distortion ratio (SNDR) and effective number of bits (ENOB) are higher for 0.35µm technology. But these advantages are at the cost of higher power dissipation. Hence there exists a trade-off between these performance metrics.


Author(s):  
Mahmud Abdoli ◽  
Esmaeil Najafi Aghdam

Developing an analog-to-digital converter (ADC) based on the time-interleaved delta–sigma modulator (TIDSM) is an appropriate technique to attain high-speed ADCs. TIDSMs can be successfully accomplished with the aid of developing the block digital filtering (BDF) method. In this approach, [Formula: see text] mutually cross-connection delta–sigma modulators are used, whereby each one of them operates at a sampling rate of [Formula: see text], leading to an effective sampling rate of [Formula: see text]. In this study, a novel structure is proposed based on the Noise Coupled time-interleaved delta–sigma modulator (NC-TIDSM) with reduced hardware complexity. This structure not only increases the overall noise transfer function (NTF) order, but also reduces the hardware element counts. The simulation results demonstrate that the SNDRs of the first-order two-channel and four-channel NC-TIDSM with reduced hardware are 13 and 15 dB better than those of their BDF technique counterparts; also, the SNDR of the second-order two-channel NC-TIDSM with reduced hardware is 8 dB better than that of their BDF technique counterpart; also, the hardware element quantities are reduced dramatically. Moreover, some practical challenges such as the finite op-amp’s gain and mismatching effects that directly affect the circuit implementation of the proposed structure have been described. Furthermore, the hardware complexity of the proposed structures is reduced considerably in comparison to that of the BDF technique with the NC-TIDSM structure.


2013 ◽  
Vol 22 (04) ◽  
pp. 1350018 ◽  
Author(s):  
ZHANGMING ZHU ◽  
HONGBING WU ◽  
GUANGWEN YU ◽  
YANHONG LI ◽  
LIANXI LIU ◽  
...  

A low offset and high speed preamplifier latch comparator is proposed for high-speed pipeline analog-to-digital converters (ADCs). In order to realize low offset, both offset cancellation techniques and kickback noise reduction techniques are adopted. Based on TSMC 0.18 μm 3.3 V CMOS process, Monte Carlo simulation shows that the comparator has a low offset voltage 1.1806 mV at 1 sigma at 125 MHz, with a power dissipation of 413.48 μW.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Labonnah Farzana Rahman ◽  
Mamun Bin Ibne Reaz ◽  
Chia Chieu Yin ◽  
Mohammad Marufuzzaman ◽  
Mohammad Anisur Rahman

Circuit intricacy, speed, low-offset voltage, and resolution are essential factors for high-speed applications like analog-to-digital converters (ADCs). The comparator circuit with preamplifier increases the power dissipation, as it requires higher amount of currents than the latch circuitry. In this research, a novel topology of dynamic latch comparator is illustrated, which is able to provide high speed, low offset, and high resolution. Moreover, the circuit is able to reduce the power dissipation as the topology is based on latch circuitry. The cross-coupled circuit mechanism with the regenerative latch is employed for enhancing the dynamic latch comparator performance. In addition, input-tracking phase is used to reduce the offset voltage. The Monte-Carlo simulation results for the designed comparator in 0.18 μm CMOS process show that the equivalent input-referred offset voltage is 720 μV with 3.44 mV standard deviation. The simulated result shows that the designed comparator has 8-bit resolution and dissipates 158.5 μW of power under 1.8 V supply while operating with a clock frequency of 50 MHz. In addition, the proposed dynamic latch comparator has a layout size of148.80 μm×59.70 μm.


2014 ◽  
Vol 23 (05) ◽  
pp. 1450059 ◽  
Author(s):  
MAO YE ◽  
BIN WU ◽  
YONGXU ZHU ◽  
YUMEI ZHOU

This paper presents the design and implementation of a 11-bit 160 MSPS analog-to-digital converter (ADC) for next generation super high-speed wireless local area network (WLAN) application. The ADC core consists of one front sample and hold stage and four cascades of 2.5 bit pipeline stages with opamp sharing between successive stages. To achieve low power dissipation at 1.2 V supply, a single stage symmetrical amplifier with double transimpedance gain-boosting amplifier is proposed. High speed on-chip reference buffer with replica source follower is also included for linearity performance. The ADC was fabricated in a standard 130-nm CMOS process and an occupied silicon area of 0.95 mm × 1.15 mm. Performance of 73 dB spurious-free-dynamic-range is measured at 160 MS/s with 1 Vpp input signal. The power dissipation of the analog core chip is only 50 mW from a 1.2 V supply.


Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2260
Author(s):  
Khuram Shehzad ◽  
Deeksha Verma ◽  
Danial Khan ◽  
Qurat Ul Ain ◽  
Muhammad Basim ◽  
...  

A low power 12-bit, 20 MS/s asynchronously controlled successive approximation register (SAR) analog-to-digital converter (ADC) to be used in wireless access for vehicular environment (WAVE) intelligent transportation system (ITS) sensor based application is presented in this paper. To optimize the architecture with respect to power consumption and performance, several techniques are proposed. A switching method which employs the common mode charge recovery (CMCR) switching process is presented for capacitive digital-to-analog converter (CDAC) part to lower the switching energy. The switching technique proposed in our work consumes 56.3% less energy in comparison with conventional CMCR switching method. For high speed operation with low power consumption and to overcome the kick back issue in the comparator part, a mutated dynamic-latch comparator with cascode is implemented. In addition, to optimize the flexibility relating to the performance of logic part, an asynchronous topology is employed. The structure is fabricated in 65 nm CMOS process technology with an active area of 0.14 mm2. With a sampling frequency of 20 MS/s, the proposed architecture attains signal-to-noise distortion ratio (SNDR) of 65.44 dB at Nyquist frequency while consuming only 472.2 µW with 1 V power supply.


Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 177
Author(s):  
Dongjun Park ◽  
Sungwook Choi ◽  
Jongsun Kim

An all-digital multiplying delay-locked loop (MDLL)-based clock multiplier featuring a time-to-digital converter (TDC) to achieve fast power-on capability is presented. The proposed MDLL adopts a new offset-free cyclic Vernier TDC to achieve a fast lock time of 15 reference clock cycles while maintaining a wide detection range and high resolution. The proposed offset-free TDC also uses a correlated double sampling technique to remove mismatch and offset issues, resulting in low jitter characteristics. After the MDLL is quickly locked, the TDC is turned off, and it goes into delta-sigma modulator (DSM)-based sequential tracking mode to reduce power consumption and improve jitter performance. Implemented in a 65-nm 1.0-V CMOS process, the proposed MDLL occupies an active area of 0.043 mm2 and generates a 2.4-GHz output clock from a 75-MHz reference clock (multiplication factor N = 32). It achieves an effective peak-to-peak jitter of 9.4 ps and consumes 3.3 mW at 2.4 GHz.


Author(s):  
Eka Fitrah Pribadi ◽  
Rajeev Kumar Pandey ◽  
Paul C.-P. Chao

Abstract A high-resolution, low offset delta-sigma analog to digital converter for detecting photoplethysmography (PPG) signal is presented in this study. The PPG signal is a bio-optical signal incorporated with heart functionality and located in the range of 0.1–10 Hz. The location to get PPG signal is on a pulsating artery. Thus the delta-sigma analog-to-digital (DS ADC) converter is designed specifically in that range. However, the DS ADC circuitry suffers from 1/f noise under 10 Hz frequency range. A chopper based operational amplifier is implemented in DS ADC to push the 1/f noise into high-frequency noise. The dc offset of the operational amplifier is also pushed to the high-frequency region. The DS ADC circuitry consists of a second-order continuous-time delta-sigma modulator. The delta-sigma modulator circuitry is designed and simulated using TSMC 180 nm technology. The continuous-time delta-sigma modulator active area layout is 746μm × 399 μm and fabricated using TSMC 180 nm technology. It operates in 100 Hz bandwidth and 4096 over-sampling ratios. The SFDR of the circuit is above 70 dB. The power consumption of the delta-sigma modulator is 35.61μW. The simulation is performed in three different kinds of corner, SS, TT, and FF corner, to guarantee the circuitry works in different conditions.


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