一种高速开关电容动态锁存比较器分析与设计

设计了一种基于CMOS工艺的开关电容动态锁存比较器。该比较器包含一个共模不敏感全差分开关电容采样级和一级动态锁存比较器。开关电容采样级验证了比较器的输入共模范围,动态锁存器采用两个正反馈锁存器和额外的反馈环路提高了锁存的速度。基于0.18μm 1.8V CMOS工艺进行了版图设计和后仿真,结果表明该比较器可以应用于200 MSPS高精度流水线模数转换器。     

一种分辨率为39μV的高精度比较器设计

该文主要介绍了一个应用于12bit SAR ADC中的高精度比较器。基于预放大锁存理论,完成了预放大级、锁存比较级和输出缓冲级三个模块的设计。为达到所需比较器的精度,对预放大级进行优化设计,锁存比较级电路采用的是动态锁存结构,而输出缓冲级采用的是SR锁存电路。该比较器是在GSMC 0.18μm工艺下完成仿真设计的,经测试,在300M时钟下,比较器的分辨率为39μV。     

低功耗高精度的电压比较器设计

设计了一款用于实现10位精度逐次逼近型模数转换器(SAR ADC)的电压比较器,该比较器采用高速高精度比较器结构并进行了优化,在高速度、低功耗锁存器的基础上加预放大级以提高比较精度,加RS触发器优化处理比较器的输出信号。同时,采用失调校准技术消除失调,预放大级采用共源共栅结构抑制回程噪声,最终获得了高精度和较低的功耗。仿真结果表明:在Chartered 0.35μm 2P4MCMOS工艺下,时钟频率5 MHz,电源电压3.3 V,分辨率达0.1 mV,平均功耗约为0.45 mW,芯片测试结果表明比较器满足了SAR ADC的要求。     

用于高速高精度流水线ADC的开关电容比较器

在65 nm CMOS工艺条件下,设计了一种用于高速高精度流水线ADC的开关电容比较器。采用单电容结构,实现了比较结果的最小化传输延迟。利用正反馈电容将采样网络的实极点调制为复极点,以减小采样传输延迟。用静态锁存器替代高速双尾动态锁存器,以适应正反馈的电容结构。数字驱动部分采用正反馈方式,以提升传输速度。Spectre仿真结果表明,在14位精度下,10 GHz带宽比较器的采样网络具有与20 GHz带宽MDAC的采样网络相同的传输延迟,从锁存器开始锁存到数字驱动输出的总传输延迟小于50 ps。     

A 0.5 V offset cancelled latch comparator in standard 0.18 μm CMOS process

This paper presents a new 0.5 V high-speed dynamic latch comparator with built-in foreground offset cancellation capability and rail-to-rail input range. Traditional latch comparators lose their speed performance in low voltage condition, especially in sub-1V applications. The proposed latch comparator utilizes a speed-up technique based on a novel boosting method to mitigate the low voltage imperfections on circuit operation. Employing a new offset cancellation technique based on the same boosting capacitors is another key idea. This enhances the accuracy of the ultra low-voltage latch comparators and relaxes the need for preamplifier stage, which is conventionally used in the low offset latch comparator. The performed Monte Carlo simulations over corners in 0.18 μm standard CMOS process show the improvement of input referred offset voltage with a standard deviation of 29.9 mV/299 μV before and after offset cancellation, respectively. The designed comparator dissipates 34 μW power from 0.5 V voltage supply while operating in 200 MHz clock frequency and detects 1 mV input difference.     

A novel low-power,low-offset,and high-speed CMOS dynamic latched comparator

A novel dynamic latched comparator with offset voltage compensation is presented. The proposed comparator uses one phase clock signal for its operation and can drive a larger capacitive load with complementary version of the regenerative output latch stage. As it provides a larger voltage gain up to 22 V/V to the regenerative latch, the input-referred offset voltage of the latch is reduced and metastability is improved. The proposed comparator is designed using 90 nm PTM technology and 1 V power supply voltage. It demonstrates up to 24.6% less offset voltage and 30.0% less sensitivity of delay to decreasing input voltage difference (17 ps/decade) than the conventional double-tail latched comparator at approximately the same area and power consumption. In addition, with a digitally controlled capacitive offset calibration technique, the offset voltage of the proposed comparator is further reduced from 6.03 to 1.10 mV at 1-sigma at the operating clock frequency of 3 GHz, and it consumes 54 μW/GHz after calibration.     

A fast, latching comparator for 12 bit A/D applications

High-speed, 12 bit accurate successive approximation A/D converters demand a comparator with both excellent input specifications and fast response time. The author describes a voltage comparator with 50 ns response time to 1/2 LSB overdrive (1.2 mV) and 0.1 LSB (250 /spl mu/V) total input error. Unique features of the circuit include a super-/spl beta/ input stage, a fast buried-zener level-shift, a fully differential output stage, a floating-zener biasing scheme, and a fast latch circuit which does not interfere with input accuracy. The comparator is manufactured on a bipolar, double-implanted, thin epi, junction-isolated process.     

An improved low offset latch comparator for high-speed ADCs

This paper presents a new high-speed and low offset latch comparator. The proposed offset compensation technique for latch comparator enables the preamplifier design relaxation for high-speed and high-resolution analog-to-digital converters. Employing the negative resistance of regeneration latch to enhance the comparator gain in input tracking phase is the key idea to reduce the latch input referred offset voltage. The Monte-Carlo simulation results for the designed comparator in 0.18 μm CMOS process show that equivalent input referred offset voltage is 200 μV at 1 sigma while it was 26 mV at 1 sigma before offset cancellation. The comparator dissipates 600 μW from a 1.8 V supply while operating in 500 MHz clock frequency.     

CMOS charge-transfer preamplifier for offset-fluctuationcancellation in low-power A/D converters

We have developed a low-power, high-accuracy comparator composed of a dynamic latch and a CMOS charge transfer preamplifier (CT preamplifier). The CT preamplifier amplifies the input signal with no static power dissipation, and the operation is almost insensitive to the device parameter fluctuations. The low-power and high-accuracy comparator has been realized by combining the CT preamplifier with a dynamic latch circuit. The fluctuation in the offset voltage of a dynamic latch is reduced by a factor of the preamplifier gain. A 4-bit flash A/D converter circuit has been designed and fabricated by 0.6-μm CMOS process. Low differential nonlinearity of less than ±4 mV has been verified by the measurements on test circuits, showing 8-bit resolution capability. Very low power operation at 4.3 μW per MS/s per comparator has also been achieved     

一种应用于高速高精度模数转换器的比较器

文中设计了一种基于CMOS工艺的高速高精度时钟控制比较器。该比较器包含一个全差分开关电容采样级、一级预放大器、动态锁存器及时钟控制反相器。预放大器采用正反馈放大技术保证了增益和速度,锁存器采用两个正反馈锁存器和额外的反馈环路提高了锁存的速度。基于0.18μm 1.8V CMOS工艺进行了设计和仿真,结果表明该比较器可以应用于500 MSPS高精度流水线模数转换器。     

A high-speed CMOS comparator for use in an ADC

A dynamic latch preceded by an offset-cancelled amplifier is used in the 3-μm CMOS comparator to obtain a response time of 43 ns. The offset-cancelled amplifier reduces the input-referred offset so that medium-resolution analog-to-digital converters (ADCs) can be built with this comparator. The use of pipelining within the comparator enables the offset cancellation to be done as the dynamic latch is enabled. Power and area are optimally distributed within the amplifier to minimize response time     

基于0.18μm SiGe BiCMOS工艺的高速比较器分析与设计

基于预放大正反馈锁存比较理论,给出了一种8bit 8Gs/s高速比较器的设计.该比较器采用预放大器结构以提高分辨率、加快比较过程,采用主从锁存器降低亚稳态发生概率,采用输出缓冲器改善输出波形、提供测试接口;在HHNEC 0.18μm SiGe BiCMOS工艺下,采用Cadence Spectre进行仿真,结果显示,该比较器精度为4mV,输出摆幅±300mV,锁存时间37ps,过驱动恢复时间22ps,功耗约57mW,表现出良好的性能.     

Analysis and design of low-voltage low-power high-speed double tail current dynamic latch comparator

The demanding need of ultra-high speed, area efficient and power optimized analog-to-digital converter is forcing towards the exploration and usage of the dynamic regenerative comparator to minimize the power, area and maximize the speed. In this paper, detailed analysis of the delay for the various dynamic latch based comparators is presented and analytical expressions are derived. With the help of analytical expressions, the designer can obtain insight view of the different parameters, which are the contributors of the delay in the dynamic comparator. Based on the findings, various tradeoffs can be explored. Based on the literature and presented analysis, a new dynamic latch based comparator is proposed. The basic double tail dynamic latch based comparator and shared charge logic are modified for low-power and high-speed with the reduced power supply in the proposed comparator. With the modified structure of double tail latch comparator and adding the shared charge logic, the regeneration delay is reduced, at the same time, power consumption is also reduced. Simulation results in 90 nm CMOS technology confirm the claimed reductions. The simulation is carried out using 90 nm technology with a supply voltage of 1 V, at 1 GHz of frequency resulting into the delay of 50.9 ps while consuming 31.80 μW of power.     

A high-speed CMOS comparator with 8-b resolution

A comparator consisting of a differential input stage, two regenerative flip-flops, and an S-R latch is presented. No offset cancellation is exploited, which reduces the power consumption as well as the die area and increases the comparison speed. An experimental version of the comparator has been integrated in a standard double-poly double-metal 1.5-μm n-well process with a die area of only 140×100 μm². This circuit, operating under a +2.5/-2.5-V power supply, performs comparison to a precision of 8 b with a symmetrical input dynamic range of 2.5 V (therefore ±0.5 LSB resolution is equal to ±4.9 mV)     

一种基于VCM开关切换的12位20 MS/s SAR ADC

设计了一种12位、采样率为20 MS/s的逐次逼近型模数转换器(SAR ADC)。整体电路为全差分结构,采用了一种基于VCM开关切换的分段式电容阵列。同时,比较器结合了前置运放和动态锁存器,与异步时序相配合,实现了SAR ADC高速工作。此外,采样电路采用栅压自举技术,提高采样的线性度。芯片基于TSMC 180 nm 1P5M CMOS工艺设计。仿真结果表明,当采样率为20 MS/s时,SAR ADC有效位数为11.94 bit,无杂散动态范围为86.53 dBc,信噪比为73.66 dB。     

5位高速低功耗Binary-Search模数转换器

基于65 nm CMOS工艺,设计了一种高速低功耗二分搜索算法(Binary-Search)模数转换器(ADC)。与传统Binary-Search结构相比,该ADC的比较器采用两级动态前置放大器和一级动态闩锁器组合构成,减小了静态电流,得到极低的功耗;失调电压降低到不会引起判决误差,省去了外接的数字校准模块。因此,芯片面积减小,避免了校准模块拖慢比较器的工作速度。后仿结果表明,当采样频率为1 GHz时,该Binary-Search ADC的有效位达4.59 bit,功耗仅1.57 mW。     

一种双路移相脉冲驱动器的研制

介绍了一种模拟ＡＳＩＣ电路ＳＢ５０３双路移相脉冲驱动器的工作原理，线路设计，版图设计及研制结果。该电路内部设计朋峰值比较器，锁存器，输入过频保护及电源低压保护电路，驱动级等功能单元，可广泛应用行相控阵雷达铁氧体饱和型移相器中。     

An Analysis of Latch Comparator Offset Due to Load Capacitor Mismatch

This brief analyzes the effect of load capacitor mismatch on the offset of a regenerative latch comparator. Two analytical models are presented and compared with HSpice simulations. Our results indicate that in a typical 0.18-mum CMOS latch, a capacitive imbalance of only 1 fF can lead to offsets of several tens of millivolts     

基于Latch的CMOS动态比较器的研究

动态比较器具有高速和低功耗的优点,是现代集成电路中的重要单元。本文简单介绍了基于latch的CMOS动态比较器的基本工作原理以及国内外最新研究进展;分析了几种新型动态比较器的性能。     

An 8 bit 1 MS/s SAR ADC with 7.72-ENOB

This paper presents a low power 8-bit 1 MS/s SAR ADC with 7.72-bit ENOB. Without an op-amp, an improved segmented capacitor DAC is proposed to reduce the capacitance and the chip area. A dynamic latch comparator with output offset voltage storage technology is used to improve the precision. Adding an extra positive feedback in the latch is to increase the speed. What is more, two pairs of CMOS switches are utilized to eliminate the kickback noise introduced by the latch. The proposed SAR ADC was fabricated in SMIC 0.18 μm CMOS technology. The measured results show that this design achieves an SFDR of 61.8 dB and an ENOB of 7.72 bits, and it consumes 67.5 μ W with the FOM of 312 fJ/conversion-step at 1 MS/s sample under 1.8 V power supply.