薄膜电阻网络及数模转换器

本文介绍了采用薄膜制造技术生产的电阻网络及数模转换器，指出了电阻网络是数模转换器的关键元件，国内外部份数模转换器的特性，以及应用及发展潜力。     

数模转换器的正确选择

主要讨论了在选择一个DAC时必须考虑的重点参数，同时介绍了一些新器件所具有的特点。     

高性能数模转换器DAC900与DSP的接口设计

介绍了高速数模转换器DAC900的性能，引脚和工作方式，并给出了它与TI数字信号处理器TMS320C6211（B）的接口逻辑设计方案。     

立体声声音数模转换器的应用

ＰＣＭ１７２５是一种完整的廉价立体声声音数模转换器（ＤＡＣ），在２５６ｆｓ（ｆｓ是声音取样频率，典型值是３２ｋＨｚ、４４１ｋＨｚ或４８ｋＨｚ）或３８４ｆｓ系统时钟下工作。该ＤＡＣ包括一种三阶Δ调制器、数字内插滤波器和模拟输出放大器。ＰＣＭ１７２５...     

一种高速电流型CMOS数模转换器设计

设计了一种10位50MS/s双模式CMOS数模转换器.为了降低功耗,提出了一种修正的超前恢复电路,在数字图象信号输出中,使电路功耗降低约30%.电路用1μm工艺技术实现,其积分线性误差为0.46LSB,差分线性误差为0.03LSB.到±0.1%的建立时间少于20ns.该数模转换器使用5V单电源.在50MS/s时全一输入时功耗为250mW,全零输入时功耗为20mW,电路芯片面积为1.8mm×2.4mm.     

视频数模转换器的测试方法介绍

视频数模转换器的测试方法被广泛应用在J750、D10等自动化测试设备上,用于测试消费类电子、通信相关的芯片,如数字电视、平板电脑、手机基带芯片等。本文主要对视频DAC的测试方法进行简要的介绍和探讨。     

一种高速电流型CMOS数模转换器设计

利用 Z参数噪声网络等效电路的分析方法 ,得到了用器件 Z参数表示的微波双极晶体管噪声参数的表达式 ,通过对微波低噪声双极晶体管的高频参数进行测试和分析 ,并把器件的网络参数和物理参数相结合 ,来对器件的最小噪声系数进行计算和分析 .     

一种12位低功耗电阻串架构DAC

利用分段式电阻串结构,基于CMOS工艺设计了一款12位3.4 MHz低功耗数模转换器(DAC)芯片。结合建立速度和静态性能的设计指标,确定“5+7”式分段结构,在保证建立速度的条件下考虑到电阻的失配性,实现良好的微分非线性(DNL)和积分非线性(INL)特性。后仿真结果表明,在3.4 MHz速度下,常温下DNL为0.14 LSB,INL为1 LSB,在-40～125℃下,DNL为0.6 LSB,INL为2 LSB,并且表现出-84 dB的总谐波失真(THD),以及在3 V电压下378μW的极低功耗,版图面积缩小到1.09 mm×0.91 mm。     

Performance comparison of quadrature amplitude modulation (QAM)-based single- and double-stage digital interpolators

In this article, the performance of quadrature amplitude modulation (QAM)-based single- and double-stage digital interpolators have been compared. The basic interpolator for up-sampling can be a combination of an expander unit with an interpolation lowpass filter in cascade. Complicated implementations can be done by connecting multiple expander and low-pass filter pairs in cascade. This article presents the efficient and effective implementation of digital interpolation systems for up-sampling of single- and double-stage digital interpolators. Comparison is done in terms of spectrum of generated signal, envelope power, modulated signal trajectory, input and output constellation and noise performance. In this article, the proposed interpolation filters have been simulated in Agilent's Advanced Design System (ADS).     

基于FPGA的高性能DAC芯片测试与研究

介绍了一种基于现场可编程门阵列（FPGA,field programmable gate array）的高性能数模转换器（DAC,digital to analog converter）性能参数的回路测试方法。以FPGA、DAC和模数转换器（ADC,analog to digital converter）等元器件为硬件测试平台,将待测数字信号转换成模拟信号再转换成数字信号,经过Matlab计算和分析后得到DAC芯片的静态特性参数和动态特性参数。其中失调误差为0.036%,增益误差为3.63%,信号噪声比为58 dB,信号噪声及失真比为57.75 dB,无杂散动态范围为62.84 dB,有效位数为9.3。测试结果表明：测试方法通用性好,精确度高,成本低。     

基于过零点检测的高分辨率DAC静态测试方法研究

受到现有测试设备的限制,高精度的D/A转换器(数模转换器)测试一直是混合信号测试中的难点,本文探讨了高精度数模转换器(DAC)测试的一种新方法.该方法通过在微弱被测电平上叠加参考正弦波,测试叠加后波形的过零点在时域上的分布情况,以了解DAC的静态特性参数.该方法的优点在于充分利用了现有ADC(模数转换器)的速度优势,原...     

内嵌于DDS高速DAC的动态参数测试

对基于ATE和频谱仪的内嵌于DDS的高速DAC的动态参数进行测试实验,通过编程由ATE提供数字正弦波和时钟信号;通过频谱仪对DAC输出模拟信号采样,并通过VBT编程得到DAC的动态参数。最后将结果返回到ATE的Excel环境下与其他测试参数结果一起输出。整个流程由ATE主机控制,避免了芯片的二次测试,缩减了测试成本,实验证明在实际应用中该方法有很好的效果。     

一种基于电流输出DAC的逐次逼近A/D转换器

设计了一种12位逐次逼近A/D转换器.该A/D转换器具有四种信号输入范围,利用电阻网络使不同量程的模拟输入与内部DAC输出范围保持一致,从而使用相同的比较器和基准实现对不同范围输入信号的A/D转换;采用一种新型分段电流源结构,利用电流信号实现内部DAC及逐次比较功能.该电路采用2 μm LC2MOS工艺实现,其积分线性误差(INL)和微分线性误差(DNL)均为±1/2 LSB,最大转换时间为12 μs.     

一种基于数字后台校准技术的14 bit 500 MS/s 数模转换器

Thelinearityofcurrent-steeringdigital-to-analogconverters（DACs）atlowsignalfrequenciesismainly limited by matching properties of current sources, so large-size current source arrays are widely used for better matching. This, however, results in large gradient errors and parasitic capacitance, which degrade the spurious free dynamic range（SFDR） for high-frequency signals. To overcome this problem, calibration is an effective method.In this paper, a digital background calibration technique for current-steering DACs is presented and verified by a 14-bit DAC in a 0.13 m standard CMOS process. The measured differential nonlinearity（DNL） and integral nonlinearity（INL） are 0.4 LSB and 1.2 LSB, respectively. At 500-MS/s, the SFDR is 70 dB and 50.3 dB for signals of 5.4 MHz and 224 MHz, respectively. The core area is 0.69 mm2and the power consumption is 165 mW from a mixed power supply with 1.2 V and 3.3 V.     

一种带电流源校准的16bit高性能DAC

设计了一种带电流源校准电路的16 bit高速、高分辨率分段电流舵型数模转换器(DAC)。针对电流舵DAC中传统差分开关的缺点,提出了一种优化的四相开关结构。系统分析了输出电流、积分非线性和无杂散动态范围(SFDR)三个重要性能指标对电流舵DAC的电流源单元设计的影响,完成了电流源单元结构和MOS管尺寸的设计。增加了一种优化设计的电流源校准电路以提高DAC的动态性能。基于0.18μm CMOS工艺完成了该DAC的版图设计和工艺加工,其核心部分芯片面积为2.8 mm^2。测试结果表明,在500 MHz采样速率、100 MHz输入信号频率下,测得该DAC的SFDR和三阶互调失真分别约为76和78 dB,动态性能得到明显提升。     

A 10-bit 100 MSamples/s BiCMOS D/A Converter

This paper presents a 10-bit Digital-to-Analogue Converter (DAC) based on the current steering principle. The DAC is processed in a 0.8µm BiCMOS process and is designed to operate at a sampling rate of 100MSamples/s. The DAC is intended for applications using direct digital synthesis, and focus has been set on reducing dynamic nonlinearities to achieve a high spurious free dynamic range (SFDR) at high generated frequencies. The main part of the DAC consists of a matrix of current cells. Each current cell contains an emitter-coupled logic (ECL) flip-flop, clocked by a global ECL clock to ensure accurate clocking. A bipolar differential pair, with a cascode CMOS current sink, steered by the differential output of the ECL flip-flop, is used in each current cell to steer the current. The DAC operates at 5V, and has a power consumption of approximately 650mW. The area of the chip-core is 2.2mm × 2.2mm. The measured integral nonlinearity (INL) and differential nonlinearity (DNL) are both approximately 2 LSB. At a generated frequency of f _g0.1 f _s(f _s = 100MSamples/s) the measured SFDR is 50dB, and at f _g0.3 f _s the measured SFDR is as high as 43dB. The DAC is operating up to a sampling frequency of approximately 140MSamples/s. The DAC uses the hierarchical switching scheme and therefore the dynamic performance is not described well using the conventional glitch energy. A new energy measure that replaces the conventional glitch energy is therefore proposed. This energy measure is especially useful during the design phase.     

高速GaAs ADC与GaAs DAC研制现状

本文叙述了高速GaAs ADC与GaAs DAC的研制现状。着重介绍了在芯片上有T/H电路的闪光型ADC和在芯片上有电流源的DAC,以及它们的性能。