一个高性能低功耗10位30MS/s流水线A/D转换器

介绍了一个10位30M采样率流水线A/D转换器，通过采用运放共享技术和动态比较器，大大降低了电路的功耗. 在采样保持电路中使用一种新颖的自举（bootstrap）开关，减小了失真，使得电路在输入信号频率很高时仍具有很好的动态性能. 还提出了一种新的偏置电路结构，为增益提高运放提供了一个稳定且精确的偏置，使得增益提高运放具有较大的电压摆幅. 在30MHz采样时钟，29MHz输入信号下测试，可以得到9.16bit有效位的输出，在输入信号为70MHz时，仍然有8.75bit有效位. 电路积分非线性的最大值为0.     

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.     

10 bit 40 MS/s流水线模数转换器的研制

设计了一种10 bit 40 MS/s流水线模数转换器.通过采用自举开关和增益提升的套筒式共源共栅运放,保证了采样保持电路和级电路的性能.该模数转换器采用TSMC 0.35 p.m CMOS3.3 V工艺流片验证,芯片核心面积为5.6 jmm2.测试结果表明,该模数转换器在采样率为40 MHz输入频率为280 kHz时,获得54.5 dB的信噪比和60.2 dB的动态范围;在采样率为46 MHz输入频率为12.6 MHz时,获得52.1 dB的信噪比和60.6 dB的动态范围.     

带输入缓冲电路的12位200兆流水线模数转换器

在12 bit 200 M采样率的模数转换电路(ADC)中实现了片内CMOS输入缓冲电路,输入缓冲电路采用源极跟随器电路构架。通过分析源极跟随器的非线性特点,在输入缓冲电路中加入高通滤波电路、复制电容电路等方式,有效提高了输入缓冲电路的线性度。将该输入缓冲电路用于无数字校准的12 bit 200 M采样率的流水线型模数转换电路(ADC)中,用台积电0.18μm CMOS工艺条件下流片验证,当采样时钟为200 MHz、输入信号频率为10 MHz、振幅为1.4 V_(pp)时其失真噪声比(SNDR)为63.5 dB,无杂散动态范围(SFDR)为78.6 dBc,ADC总体功耗为500 mW。     

基于0.35 μm GeSi-BiCMOS工艺的1 GSPS采样保持电路

介绍了一种基于0.35μmGeSi-BiCMOS工艺的1GSPS采样/保持电路。该电路采用全差分开环结构,使用局部反馈提高开环缓冲放大器的线性度;采用增益、失调数字校正电路补偿高频输入信号衰减和工艺匹配误差造成的失调。在1GS/s采样率、484.375MHz输入信号频率、3.3V电源电压下进行仿真。结果显示,电路的SFDR达到75.6dB,THD为-74.9dB,功耗87mW。将该采样/保持电路用于一个8位1GSPSA/D转换器。流片测试结果表明,在1GSPS采样率,240.123MHz和5.123MHz输入信号下,8位A/D转换器的SNR为41.39dB和43.19dB。     

基于功耗优化的流水线ADC研制

提出了一种使流水线模数转换器功耗最优的系统划分方法。采用Matlab进行模拟,以信噪比(SNR)为约束,得出一定精度条件下,流水线ADC各子级分辨率和各级采样电容缩减因子的不同选取组合;又以功耗为约束,从以上多种组合中找到满足最低功耗的流水线ADC结构划分方法。基于以上分析,在SMIC 0.35μm工艺条件下,设计了一个10 bit、采样率20 MS/s的流水线ADC,并流片验证。2.1 MHz输入频率下测试,SFDR=73 dB、ENOB=9.18 bit,模拟部分核心功耗102.3 mW。     

13 bit 50 MS/s CMOS流水线ADC的设计

介绍了一种新的流水线ADC校准算法,并利用该校准算法完成了一个13 bit,50 MS/s流水线ADC的设计.该校准算法对级电路的比较器和后级电路的输出码字的出现频率进行统计,得到各个级电路输出位的真实权值,可以同时校准多种非理想因素如运放有限增益、电容失配等造成的误差.电路采用UMC 0.18μm混合工艺,1.8 V电源电压.通过SPECTRE仿真获得晶体管级级电路的输入输出关系,将其结果导入顶层行为级模型进行校准.仿真结果表明,在50 MHz采样率、5 MHz输入信号下,通过校准算法SFDR由44.1 dB提升至102.2 dB,SNDR由40.9 dB提升至79.9 dB,ENOB由6.5 bit提升至12.98 bit.     

一种新型双采样CMOS采样保持电路

应用改进的双采样技术设计了一个标准CMOS模拟工艺下、采样率为80MHz的采样保持电路.应用单一时钟控制采样以消除两相采样的不匹配;采用时钟控制的双输入端运放以消除存储效应并消除大部分失调;采用栅压自举的采样开关以减小非线性失真.仿真结果表明,在2.5V电源电压下,当输入信号频率为37MHz时,采样保持电路可获得11bit的精度,消耗13mW的功耗.     

一种10位50MHz流水线模数转换器的设计

采用每级1.5 bit和每级2.5 bit相结合的方法设计了一种10位50 MHz流水线模数转换器。通过采用自举开关和增益自举技术的折叠式共源共栅运算放大器,保证了采样保持电路和级电路的性能。该电路采用华润上华(CSMC)0.5μm 5 V CMOS工艺进行版图设计和流片验证,芯片面积为5.5 mm2。测试结果表明:该模数转换器在采样频率为50 MHz,输入信号频率为30 kHz时,信号加谐波失真比(SNDR)为56.5 dB,无杂散动态范围(SFDR)为73.9 dB。输入频率为20 MHz时,信号加谐波失真比为52.1 dB,无杂散动态范围为65.7 dB。     

基于FPGA的非线性调频信号脉冲压缩的实现

非线性调频信号在信号设计时即考虑到脉冲压缩信号距离旁瓣的抑制,无需在硬件实现中添加加权网络抑制距离旁瓣。文中介绍了非线性调频信号的设计方法,通过Matlab仿真验证了不同设计方法的非线性调频信号的脉冲压缩性能。并在FPGA仿真环境下实现了带宽30 MHz,采样率为100 MHz,输入信号量化位数为16 bit,时长为10.24 μs的线性和非线性调频信号的脉冲压缩。     

一种带二进制校正的10位100 MS/s SAR ADC

基于SMIC 65 nm CMOS工艺,设计了一种带二进制校正的10位100 MS/s逐次逼近型模数转换器(SAR ADC),主要由自举开关、低噪声动态比较器、电容型数模转换器(C-DAC)、异步SAR逻辑以及数字纠错电路组成。电容型数模转换器采用带2位补偿电容的拆分单调电容转换方案,通过增加2位补偿电容,克服了电容型数模转换器在短时间内建立不稳定和动态比较器失调电压大的问题,使SAR ADC的性能更加稳定。数字纠错电路将每次转换输出的12位冗余码转换成10位的二进制码。使用Spectre进行前仿真验证,使用Virtuoso进行版图设计,后仿真结果表明,当电源电压为1.2 V、采样率为100 MS/s、输入信号为49.903 MHz时,该ADC的SNDR达到58.1 dB,而功耗仅为1.3 mW。     

An 11.1 mW 42 MS/s 10 b ADC With Two-Step Settling in 0.18 m CMOS

A pipelined analog-to-digital converter (ADC) uses switched-capacitor stages that settle in two steps that occur sequentially in time. The first step of settling places charge onto the load capacitance using charge pumps, and the second fulfills the settling requirements using typical negative feedback around an operational amplifier. Hence, the design combines the efficiency of a fast charge-transfer phase with the gain and noise-immunity advantages of amplifier-driven settling. Improved conversion efficiency results from a higher ratio of current delivered to the load to that consumed in static biasing. Additional circuitry constrains critical amplifier node voltages during the charge transfer, facilitating a graceful transition to amplifier-driven settling. The two-step settling technique is demonstrated in a 2.5 bit/stage 10-bit pipelined ADC that consumes 11.1 mW while sampling a 21.3 MHz input signal at 42 MS/s. The resulting SNDR is 55.6 dB $rm (ENOB = 8.94)$ and the SFDR is 67.5 dB.      

一种12位80 MS/s CMOS流水线ADC设计

介绍了一种12 bit 80 MS/s流水线ADC的设计,用于基带信号处理,其中第一级采用了2.5 bit级电路,采样保持级采用了自举开关提高线性,后级电路采用了缩减技术,节省了芯片面积.采用了折叠增益自举运放,优化了运放的建立速度,节省了功耗.芯片采用HJTC0.18μm标准CMOS工艺,1.8 V电压供电,版图面积2.3 mm × 1.4 mm.版图后仿真表明,ADC在8 MHz正弦信号1 V峰值输入下,可以达到11.10 bit有效精度,SFDR达到80.16 dB,整个芯片的功耗为155 mW.     

一种1.8V 10位100Ms/s流水线模数转换器设计

针对自举开关中的寄生效应和导通电阻的非线性问题提出了一种新的低压低电阻的自举开关.同时利用增益增强技术设计高直流增益和高单位增益带宽的运放,从而保证采样保持电路和子级电路的性能.基于以上技术,设计了一个10位100Ms/s流水线模数转换器,该模数转换器用0.18μm CMOS工艺流片验证.经测试,该模数转换器可以在采样率为100MHz,输入频率分别为在6.26和48.96MHz的情况下分别获得54.2和49.8dB的信噪比.     

一个低电压低功耗10位30MS/s流水线A/D转换器

实现了一个10位精度,30MS/s,1.2V电源电压流水线A/D转换器,通过采用运放共享技术和动态比较器,大大降低了电路的功耗。为了在低电源电压下获得较大的摆幅,设计了一个采用新颖频率补偿方法的两级运放,并深入分析了该运放的频率特性。同时还采用了一个新的偏置电路给运放提供稳定且精确的偏置。在30MHz采样时钟,0.5MHz输入信号下测试,可以得到8.1bit有效位的输出,当输入频率上升到60MHz(四倍奈奎斯特频率)时,仍然有7.9bit有效位。电路积分非线性的最大值为1.98LSB,微分非线性的最大值为0.7LSB。电路采用0.13μmCMOS工艺流片验证,芯片面积为1.12mm2,功耗仅为14.4mW。     

A 1.8-V 22-mW 10-bit 30-MS/s Pipelined CMOS ADC for Low-Power Subsampling Applications

This paper describes a 10-bit 30-MS/s subsampling pipelined analog-to-digital converter (ADC) that is implemented in a 0.18 mum CMOS process. The ADC adopts a power efficient amplifier sharing architecture in which additional switches are introduced to reduce the crosstalk between the two opamp-sharing successive stages. A new configuration is used in the first stage of the ADC to avoid using a dedicated sample-and-hold amplifier (SHA) circuit at the input and to avoid the matching requirement between the first multiplying digital-to-analog converter (MDAC) and flash input signal paths. A symmetrical gate-bootstrapping switch is used as the bottom-sampling switch in the first stage to enhance the sampling linearity. The measured differential and integral nonlinearities of the prototype are less than 0.57 least significant bit (LSB) and 0.8 LSB, respectively, at full sampling rate. The ADC exhibits higher than 9.1 effective number of bits (ENOB) for input frequencies up to 30 MHz, which is the twofold Nyquist rate (fs/2), at 30 MS/s. The ADC consumes 21.6 mW from a 1.8-V power supply and occupies 0.7 mm², which also includes the bandgap and buffer amplifiers. The figure-of-merit (FOM) of this ADC is 0.26 pJ/step.     

Acquisition time minimisation techniques for high-speed analoguesignal processing

Acquisition time minimisation techniques using a two-stage amplifier for high-speed analogue signal processing in mixed-mode circuits are presented. The proposed techniques reduce overshoots and undershoots of the amplifier by adjusting its transconductance and achieve high-speed performance with little modification to the conventional amplifier architecture. The measured signal-to-noise-and-distortion ratio of the prototype 12 bit CMOS ADC based on the proposed techniques is improved by >5 dB at a 50 MHz sampling clock     

A 15-b, 5-Msample/s low-spurious CMOS ADC

A 5-5-5-6-b pipelined analog-to-digital converter (ADC) architecture alleviates the requirements for initial capacitor matching and residue amplifier settling accuracy. The two 5-b most significant bit (MSB) stages are digitally calibrated to implement a 15-b, 5-Msample/s low-spurious ADC using 1.4-μm CMOS. A skip-and-fill algorithm with nonlinear interpolation also opens up the possibility of calibrating ADC's in the background synchronously with their normal operation. Interpolation results for the background calibration are compared with the foreground calibration results. The prototype ADC exhibits a differential nonlinearity (DNL) of +0.75/-0.6 least significant bit (LSB), an integral nonlinearity (INL) of +1.77/-1.58 LSB, and all spurious components are suppressed to below -93 dB when sampled at 5 MHz. The chip occupies 27 mm², and the analog part consumes 60 mW at 5 V. Memory and arithmetic units for calibration are supplied externally in testing     

A 12 bit 100 MS/s pipelined analog to digital converter without calibration

A 1.8 V 12 bit 100 MS/s pipelined analog to digital converter(ADC) in a 0.18μm complementary metal-oxide semiconductor process is presented.The first stage adopts a 3.5 bit structure to relax the capacitor matching requirements.A bootstrapped switch and a scaling down technique are used to improve the ADC's linearity and save power dissipation,respectively.With a 15.5 MHz input signal,the ADC achieves 79.8 dB spurious-free dynamic range and 10.5 bit effective number of bits at 100 MS/s.The power consumpt...