一个不含有传统采样保持放大器的8位100兆采样率流水线模数转换器

本文实现了一个省去传统的采样保持模块的8位100兆采样率流水线模数转换器(ADC)。与包含传统采样保持模块的相同指标的流水线ADC相比,品质因子(FoM)和面积分别降低了21%和12%。提出了一种余量增益放大器(MDAC)中运放的闭环带宽(BWclose)的模型,并通过晶体管级仿真验证了该模型。本设计采用0.18µm 1P6M CMOS混合信号工艺实现,测试结果显示,当采样率为100兆时,输入信号1MHz和80MHz对应的分辨率分别为7.43bit和6.94位,包括内置参考电压/电流源的静态功耗为23.4mW,品质因子为0.85pJ/step,面积为0.53mm2,积分非线性(INL)和差分非线性(DNL)分别为-0.99~0.76LSB,-0.49~0.56LSB。     

低功耗12b 40M流水线模数转换器

本文介绍了一个12b 40M流水线模数转换器（ADC）,在0.18um CMOS工艺下流片,工作电压3.3V,功耗76mW。为了实现功耗优化,流水线各级采用了多比特结构和套筒式运算放大器。模数转换器的前两级采用3比特/级结构,以提高转换器线性度。该模数转换器不需要校正,经测试DNL小于0.51-LSB,INL小于1LSB。当模数转换器工作在40MHz采样率时,在奈奎斯特频率以内,SNDR指标大于67dB;在49MHz以内的输入信号频带内,SFDR指标在80dB左右,变化幅度不超过1-dB。     

一个13位8兆采样率流水线模数转换器

A 13-bit 8 MSample/s high-accuracy CMOS pipeline ADC is proposed. At the input, the sample-andhold amplifier （SHA） is removed for low power and low noise; meanwhile, an improved sampling circuit is adopted to alleviate the clock skew effect. On-chip bias current is programmable to achieve low power dissipation at different sampling rates. Particularly, drain-to-source voltages in the operational amplifiers （opamps） are fixed to ensure high DC gain within the variant range of the bias current. Both on-chip and off-chip decoupling capacitors are used in the voltage reference circuit in consideration of low power and stability. The proposed ADC was implemented in 0.18-μm 1P6M CMOS technology. With a 2.4-MHz input, the measured peak SNDR and SFDR are 74.4 and 91.6 dB at 2.5 MSample/s, 74.3 and 85.4 dB at 8.0 MSample/s. It consumes 8.1, 21.6, 29.7, and 56.7 mW （including I/O drivers） when operating at 1.5, 2.5, 5.0, and 8.0 MSample/s with 2.7 V power supply, respectively. The chip occupies 3.2 mm^2, including I/O pads.     

一个1.2伏CMOS0.13微米工艺19.2毫瓦10位30兆采样率流水线模数转换器

A 10-bit 30-MS/s pipelined analog-to-digital converter (ADC) is presented. For the sake of lower power and area, the pipelined stages are scaled in current and area, and op amps are shared between the successive stages. The ADC is realized in the 0.13-μ m 1-poly 8-copper mixed signal CMOS process operating at 1.2-V supply voltage. Design approaches are discussed to overcome the challenges associated with this choice of process and supply voltage, such as limited dynamic range, poor analog characteristic devices, the limited linearity of analog switches and the embedded sub-1-V bandgap voltage reference. Measured results show that the ADC achieves 55.1-dB signal-to-noise and distortion ratio, 67.5-dB spurious free dynamic range and 19.2-mW power under conditions of 30 MSPS and 10.7-MHz input signal. The FoM is 0.33 pJ/step. The peak integral and differential nonlinearities are 1.13 LSB and 0.77 LSB, respectively. The ADC core area is 0.94 mm².     

一个用于12位40-MS/s低功耗流水线ADC的MDAC电路设计

文中设计了一个用于12位40MHz采样率低功耗流水线ADC的MDAC电路.通过对运放的分时复用,使得一个电路模块实现了两级MDAC功能,达到降低整个ADC功耗的目的.通过对MDAC结构的改进,使得该模块可以达到12bit精度的要求.通过优化辅助运放的带宽,使得高增益运放能够快速稳定.本设计在TSMC0.35μmmixsignal3.3V工艺下实现,在40MHz采样频率下,以奈奎斯特采样频率满幅(Vpp=2V)信号输入,其SINAD为73dB,ENOB为11.90bit,SFDR为89dB.整个电路消耗的动态功耗为9mW.     

一种采用改进放大器的12位40兆采样率的流水线模数转换器

本文设计实现了一种采用改进放大器的12位40兆采样率的流水线模数转换器。基于该模数转换器的结构,本文分析了影响模数转换器的精度的放大器非理想因素,并提出了针对放大器的补偿技术。该技术消除了增益提高技术和开关电容共模反馈结构对放大器的带宽和相位裕度的限制。整个模数转换器使用0.35μm标准CMOS工艺设计制作。测试结果表明,该模数转换器能够在2V输入范围内,40兆赫兹采样时钟下实现60.5dB信噪失真比和74.5dB的无杂散动态范围。     

12位100 MS/s流水线A/D转换器的参考电压缓冲器

分析了参考电压精度对流水线A/D转换器性能的影响,并通过Matlab建模仿真,得到了12位流水线A/D转换器对参考电压精度的要求,即参考电压精度要达到10位以上.提出了一种新型的参考电压缓冲器结构,通过增加两个静态比较器,有效地提高了缓冲器的精度.采用SMIC 0.35 μm 3.3 V CMOS工艺,为一个12位100 MHz采样频率的流水线A/D转换器设计了电压值为1.65 V±0.5 V的参考电压输出缓冲器.Hspice后仿真结果显示,各个工艺角下,缓冲器可将干扰对1 V的差分输出的影响控制在0.35 mV以内.该缓冲器可以达到10位以上精度,能够满足12位100 MS/s流水线A/D转换器的设计要求.     

一个没有采用校准技术的12位分辨率100兆采样率的流水线模数转换器

本文给出了一个基于0.18um CMOS工艺的12bit 100MS/s的流水线ADC。其中第一级采用了3.5比特结构以降低对电容匹配的要求,采样保持放大器、第一级和第二级均采用了自举开关以改善ADC线性度,后级采用级缩减技术节省了功耗和面积。当输入信号频率为15.5MHz、采样率为100MHz时,该ADC达到了79.8dB的SFDR和10.5bit的有效位数。芯片采用1.8V电压供电,包含输出驱动的总功耗为112mW, 芯片面积为3.51mm2 。     

用于流水线ADC的全差分参考电压电路

为了实现流水线ADC的带隙基准电压低于1 V和降低参考电压电路的功耗,提出了一种新的全差分参考电压电路。在传统带隙基准的基础上,该参考电压电路增加了MOS管基-射极电阻,可根据电阻的比例系数来调节输出带隙基准电压。采用电流模电路,实现了单端信号转差分信号,结构简单。采用TSMC 0.18 μm CMOS工艺进行设计与仿真,结果表明,温度为25 ℃时,该电路的参考电压VREFP和VREFN分别为1.156 V和0.656 V。在-40 ℃~125 ℃范围内变化时,参考电压的波动小于6 mV,温度系数小于4.6×10-5/℃。低频时,电源抑制比为115 dB。该参考电压电路应用于高清视频信号处理的流水线ADC中,能实现170 MS/s、10位精度的数模转换。     

A low power 12-bit 30 MSPS CMOS pipeline ADC with on-chip voltage reference buffer

A 12-bit 30 MSPS pipeline analog-to-digital converter(ADC) implemented in 0.13-μm 1P8M CMOS technology is presented.Low power design with the front-end sample-and-hold amplifier removed is proposed.Except for the first stage,two-stage cascode-compensated operational amplifiers with dual inputs are shared between successive stages to further reduce power consumption.The ADC presents 65.3 dB SNR,75.8 dB SFDR and 64.6 dB SNDR at 5 MHz analog input with 30.7 MHz sampling rate.The chip dissipates 33.6 mW from 1.2 V power supply.FOM is 0.79 pJ/conv step.     

8位12MS/s带片上参考电压的异步逐次逼近模数转换器

This paper proposes an 8 bit asynchronous successive approximation register ADC for wireless transceivers.A split capacitor DAC is used to reduce power and area consumption and the value of the split capacitor is calculated theoretically to ensure linearity.Asynchronous control logic is proposed to eliminate the high internal clocks and significantly speeds up the successive approximation algorithm.An on-chip reference with a fully integrated buffer and decoupling capacitor is adopted for avoiding an extra pin for the off-chip reference. The prototype,fabricated in UMC 0.18μm CMOS technology,achieves an effective number of bits of 7.64 bits at a sampling frequency of 12 MS/s.The total power consumption is 0.918 mW for a 1.8 V supply,while the onchip reference consumes 53%of the total power.It achieves a figure of merit of 180 fJ/conv-step,excluding the reference’s power consumption.     

A 10-bit 50 MS/s SAR ADC in 65 nm CMOS with on-chip reference voltage buffer

This paper presents the design of a 10-bit, 50 MS/s successive approximation register (SAR) analog-to-digital converter (ADC) with an on-chip reference voltage buffer implemented in 65 nm CMOS process. The speed limitation on SAR ADCs with off-chip reference voltage and the necessity of a fast-settling reference voltage buffer are elaborated. Design details of a high-speed reference voltage buffer which ensures precise settling of the DAC output voltage in the presence of bondwire inductances are provided. The ADC uses bootstrapped switches for input sampling, a double-tail high-speed dynamic comparator and split binary-weighted capacitive array charge redistribution DACs. The split binary-weighted array DAC topology helps us to achieve low area and less capacitive load and thus enhances power efficiency. Top-plate sampling is utilized in the DAC to reduce the number of switches. In post-layout simulation which includes the entire pad frame and associated parasitics, the ADC achieves an ENOB of 9.25 bits at a supply voltage of 1.2 V, typical process corner and sampling frequency of 50 MS/s for near-Nyquist input. Excluding the reference voltage buffer, the ADC consumes 697 μW and achieves an energy efficiency of 25 fJ/conversion-step while occupying a core area of 0.055 mm².     

A low power 12-b 40-MS/s pipeline ADC

This paper describes a 12-bit, 40-MS/s pipelined A/D converter (ADC) which is implemented in 0.18-μm CMOS process drawing 76-mW power from 3.3-V supply. Multi-bit architectures as well as telescopic operational transconductance amplifiers (OTAs) are adopted in all pipeline stages for good power efficiency. In the first two stages,particularly, 3-bit/stage architectures are used to improve the ADC's linearity performance. The ADC is calibration-free and achieves a DNL of less than 0.51 LSB and an INL of less than 1 LSB. The SNDR performance is above 67 dB below Nyquist. The 80-dB SFDR performance is maintained within 1 dB for input frequencies up to 49 MHz at full sampling rate.     

An 8-bit 100-MS/s pipelined ADC without dedicated sample-and-hold amplifier

An 8-b 100-MS/s pipelined analog-to-digital converter(ADC) is presented.Without the dedicated sample-and -hold amplifier(SHA),it achieves figure-of-merit and area 21%and 12%less than the conventional ADC with the dedicated SHA,respectively.The closed-loop bandwidth of op amps in multiplying DAC is modeled,providing guidelines for power optimization.The theory is well supported by transistor level simulations.A 0.18-μm 1P6M CMOS process was used to integrate the ADCs,and the measured results show that the...     

A 12-bit 40 MS/s pipelined ADC with over 80 dB SFDR

This paper describes a 12-bit 40 MS/s calibration-free pipelined analog-to-digital converter (ADC), which is optimized for high spurious flee dynamic range (SFDR) performance and low power dissipation. With a 4.9 MHz sine wave input, the prototype ADC implemented in a 0.18-μm 1P6M CMOS process shows measured differential nonlinearity and integral nonlinearity within 0.78 and 1.32 least significant bits at the 12-bit level without any trimming or calibration. The ADC, with a total die area of 3. 1 × 2.1 mm~2, demonstrates a maximum signal-to-noise distortion ratio (SNDR) and SFDR of 66.32 and 83.38 dB, respectively, at a 4.9 MHz analog input and a power consumption of 102 mW from a 1.8 V supply.     

一个SFDR性能超过80dB的12-bit 40MS/s流水线模数转换器

摘要：本文介绍了一个以高无杂散动态范围(SFDR)和低功耗为优化目标,不需要校正的12-bit,40MS/s流水线模数转换器(ADC)。以4.9MHz正弦输入信号测试表明,本ADC微分非线性(DNL)的最大值为0.78LSB,积分非线性(INL)的最大值为1.32LSB,信噪失真比(SNDR)为66.32dB,SFDR为83.38dB。电路采用 0.18-um 1P6M CMOS工艺实现,整体芯片面积3.1mm×2.1mm,电源电压1.8V,功耗102mW。     

一种低功耗11位100MS/s采样率SAR ADC IP

本文介绍了一种双通道11位100MS/s采样率的混合结构SAR ADC IP。每个通道均采用flash-SAR结构以达到高速低功耗的目的。为了进一步降低功耗,flash和SAR中的比较器均采用全动态比较器。SAR中逐次逼近逻辑所需要的高速异步触发时钟采用门控环形振荡器产生。为了提高电容的匹配性,在版图设计中,采用底板包围顶板的MOM电容结构,有效减小电容寄生。本设计制造工艺为SMIC55nm的低漏电CMOS工艺,双通道的总面积为0.35mm2且核心面积仅为0.046 mm2。双通道模数转换器在1.2V供电电压下消耗的总电流为2.92mA。在2.4MHz输入和50MHz输入下的有效转换位数（ENOB）分别为9.9位和9.34位。计算得出本设计的FOM值为18.3fJ/conversion-step。