Design of highperformance pipeline analogto digital. Digital calibration is shown as a technique to improve nonidealities which arise due to low dc gain in opamps, and capacitor mismatch in pipelined adcs. The adc has 8 stage, that expect amplifiers the other elements are ideal. At unfortunately by enhancement of resolution, power the front end, the sample and. The proposed rapid calibration scheme enables significantly shorter. High performance sar ad converter with calibration. Improving accuracy and energy efficiency of pipeline analog. It was shown for a desired settling accuracy, mdac opamps require. Because adc circuits take in an analog signal, which is continuously variable, and resolve it into one of many discrete steps, it is important to know how many of these steps there are in total. The successive approximation adc has a very simple structure, low power, and reasonably fast. The first technique enables rapid background digital correction of both dac and gain errors in the multibit first stage of an 11bit pipelined adc. Jasbir kaur, 2saurabh kansal 1assistant professor, 2me scholar electronics vlsi design electronics and communication engineering department pec university of technology, chandigarh, india abstractthe performance of the analog to digital. Directconversion adcs are a class of adcs that operate at very high speeds, because.
The pipelined adc is a practical and efficient structure for moderate speed1200mss, moderate resolution 1016 bits adcs. As such, when designing a pipelined adc a clear understanding of the design tradeoffs, and state of the art techniques is required to implement todays pipelined adcs have seen phenomenal improvements in performance in recent years. The pic32 12bit highspeed successive approximation register sar analogtodigital converter adc includes the following features. Cascade several low resolution stages to obtain high overall resolution.
Large dc gain and large capacitors are shown to be necessary to achieve high linearity in a pipelined adc. As verification of the proposed design methodology, a 10bit 40mhz pipeline analogtodigital converter prototype is developed in commercial tsmc 90nm cmos technology. Pipelined adc design and enhancement techniques springerlink. Choose the right data converter for your application. Pipelined adcs have seen phenomenal improvements in performance over the last few years. Pipelined adc design and enhancement techniques analog circuits and signal processing. In this work three techniques to improve pipelined adc performance with respect to linearity and power consumption are presented. In this thesis, two novel accuracy improvement techniques to overcome the accuracy limit set by analog building blocks opamps and capacitors in the context of lowvoltage and highspeed pipelined adc design are presented. The second technique develops a new mdac topology which enables a pipelined adc to be designed without a frontend sampleandhold, and thus allows for. Basic block of pipelined adc design requirements vilem kledrowetz, jiri haze dept. University of science and technology of china 1993 m.
A design tradeoff which exists for pipeline adcs is the choice between a larger number of bits resolved per stage hence less latency, but more design complexity, or a fewer number of bits. Monotonic multiswitching method for ultralowvoltage energy. The first is a capacitor and opamp sharing technique that reduces the load on the first stage opamp by three fold. Practical considerations of adc circuits chapter digitalanalog conversion pdf version. Bibhudatta sahoo university of illinois at urbanachampaign. We believe in bringing together your team and ours early in the concept phase to develop the most cost effective design for fabrication and assembly. Accuracy enhancement techniques in lowvoltage high.
Design challenges and improvement techniques for sar adc. Our approach to product development is based on team work. Butterfield 1 12bit pipelined adc design project justin d. Over the last 15 years, digital performance has increased 150 times more than anal 1. Design of highspeed analogtodigital converters using low. Pipelined adc design and enhancement techniques by imran. Highperformance pipeline ad converter design in deep. Title digital gain error correction technique for 8bit pipeline adc forfattare author khalid javeed sammanfattning abstract an analogtodigital converter adc is a link between the analog and digital domains and plays a vital role in modern mixed signal processing systems. Pipelined adc design and enhancement techniques ebook por.
Electrical engineering and computer sciences in the graduate division of the university of california, berkeley. Pipelined adc design and enhancement techniques analog circuits and signal processing ahmed, imran on. Modeling and implementation of a 6 bit, 50mhz pipelined. As such, when designing a pipelined adc a clear understanding of the design tradeoffs, and state of the art techniques is required to implement todays high performance low power adcs. In addition, it explores the limitations of pipelined sar adcs, which recently have demonstrated high power efficiency at conversion rates of several tens of mss and sndr 65 db. Pipeline adc with a nonlinear gain stage and digital. The goal of this major qualifying project is to design and fabricate a 16bit 10mhz pipeline analog to digital converter adc using 0. Below is a simulink model for a pipelined adc including nonidealities such as offsets, matching, and noise.
At unfortunately by enhancement of resolution, power the front end, the. Driver circuit design of switchedcapacitor successive approximation register sar analogtodigital converters adc is critical. Design and implementation a 8 bits pipeline analog to. Study of various adcs and compare their performance and. Adc1 control register 1 this register controls the basic operation of the adc module, including behavior in sleep and idle modes, and data formatting. Sensor data is lost andor adc dynamic range is not fully utilized because the spans are unequal, start at different dc voltages, or both. As cmos technologies improve and smaller process sizes lead to an increase in the implementation of digital signal processing, the potential for digital correction and calibration of adcs has. A low power, middleresolution 710 bit, middle speed 20mhz200mhz pipelined adc is an important block in modern applications of telecommunication, consumer electronics, and medical electronics. Pipeline adc block diagram university of california. Adcs by their dac structures, conversionspeed enhancement techniques. Sensor to adcanalog interface design introduction the sensor output voltage span seldom equals the analogtodigital converter adc input voltage span. The motivation for designing a pipeline adc comes from the desire to characterize and test the functionality of the novel split adc architecture concept 1 using a nonalgorithmic adc. A 15bit radix4 pipeline adc 6, 7 has been simulated in matlab for illustration validity of calibration method. Accuracy enhancement techniques in lowvoltage highspeed pipelined adc design public deposited.
Many good adc architectures have been invented to satisfy different requirements in different applications. Use of multibitperstage architecture and design optimization can achieve 14bit performance as demonstrated in 5, but most pipelined adcs with more than 12bit resolution will usually require some kind of linearity enhancement techniques. As such, when designing a pipelined adc a clear understanding of the design tradeoffs, and state of the art techniques is required to implement todays high performance low. Written for both researchers and professionals, pipelined. Practical considerations of adc circuits digitalanalog. Through the aid of new techniques and concepts, the power dissipation of lowto medium resolution adcs benefit from going to more modern cmos processes. This thesis project aims at modeling and implementation of a pipelined adc with high speed and low power consumption. Department of electrical and computer engineering university of toronto abstract in this work three techniques to improve pipelined adc performance with respect to linearity and power consumption are presented. Design techniques for ultrahighspeed timeinterleaved.
Accuracy enhancement techniques in lowvoltage highspeed. Highperformance pipeline ad converter design in deepsubmicron cmos by yun chiu b. Through the aid of new techniques and concepts, the power dissipation of lowtomedium resolution adcs benefit from going to more modern cmos processes. Correction of nonideal amplifiers effect in pipelined adcs. Finally, residue amplifier pipeline adcs offer a few advantages over typical flash adcs. Adc snr is shown to be related to capacitor area, where to achieve a high snr large capacitors are required. Pdf pipelined adc design and enhancement technqiues. This research investigates the design of highspeed sar adcs to identify circuit techniques that improve their conversion speed while maintaining low energy operation. Pipelined adc design a tutorial based on slides from dr. This dissertation presents the design of three highperformance successiveapproximationregister sar analogtodigital converters adcs using distinct digital background calibration techniques under the framework of a generalized codedomain linear equalizer.
Low power design techniques for high speed pipelined adcs public deposited. The digital outputs from adc are executed in the digital signal processor dsp. Pipeline adc with a nonlinear gain stage and digital correction a major qualifying project submitted to the afculty. Design considerations the first step in the design is to setup the comparators and multiplexers for the 1. Pipelined adc design and enhancement techniques analog. Pipeline adc with a nonlinear gain stage and digital correction. Pipelined adc design and key tradeoffs are discussed. Circuit techniques used include a precise comparator, operational amplifier and clock management. Background calibration techniques for multistage pipelined. Study of various adcs and compare their performance and parameters 1mrs. Design techniques for ultrahighspeed timeinterleaved analogtodigital converters adcs by yida duan a dissertation submitted in partial satisfaction of the requirements for the degree of doctor of philosophy in engineering. Improving accuracy and energy efficiency of pipeline. Introduction the goal of this project is to design a 12bit pipeline analog to digital converter adc. Detailed knowledge of the behavior in a system allows the adc design margin to be minimized thus saving cost and power consumption.
The model resolution is very flexible, and system level techniques are easily added. Background calibration techniques for multistage pipelined adcs. Because adc circuits take in an analog signal, which is continuously variable, and resolve it into one of many. This leads to use digital calibration technique which relaxes design. Sampling frequency is 100 mhz and desired adc is chosen a 15bit sigmadelta. Pdf basic block of pipelined adc design requirements. As we can see from the flash adc architecture shown in figure 1, the number of comparators and logic elements in a flash adc is on the order of 21, where n is the number of bits, we can see the number of components doubles with each additional bit. Review of analogtodigital conversion characteristics and design. Although the highest performance monolithic pipelined adcs are still built in. The pipeline analogtodigital converter adc architecture is the most popular topology for video processing,telecommunications,digital imaging etc. Pipeline adc block diagram university of california, berkeley. In addition, it explores the limitations of pipelinedsar adcs, which recently have demonstrated high power efficiency at conversion rates of several tens of mss and sndr 65 db. Written for both researchers and professionals, pipelined adc design and enhancement techniques provides.
Architecture complexity is proportional to the resolution n nj throughput is significantly improved relative to algorithmic or sar digital redundancy works the same way as algorithmic interstage gain enables stage scaling to save power and area. Design and implementation a 8 bits pipeline analog to digital. Pipelined adc enhancement techniques computer engineering. Monotonic multiswitching method for ultralowvoltage. High performance sar ad converter with calibration techniques. A new approach for low power adc design nicholas wood erik jonsson school of engineering and computer science the university of texas at dallas richardson, texas, 750803021 email. Applications of sar adc is used widely data acquisition techniques at the sampling rates higher than. Adc has a unique experience in solving complex problems through product and process engineering. Resolution is the number of binary bits output by the converter. Butterfield boise state university december 15, 2011 1. Mdac design considerations capacitor matchinglinearity. Modeling and implementation of a 6 bit, 50mhz pipelined adc. In switchedcapacitor techniques for highaccuracy filter and adc design, alternative sc techniques are proposed which allow the achievement of higher.
Perhaps the most important consideration of an adc is its resolution. In the proposed technique, design problems of analogue circuits are moved inside. A switched capacitor is used to sample and multiplying at each stage. This paper describes a 8 bits, 20 msampless pipeline analogtodigital converter implemented in 0. As cmos technologies improve and smaller process sizes lead to an increase in the implementation of digital signal processing, the potential for digital correction and calibration of adcs has emerged. Trimming is one such method, but it cannot track varia. In the work included in this thesis an accurate model of a successiveapproximation adc is developed. Low power design techniques for high speed pipelined adcs. However, these techniques are difficult to apply on the middle resolution and middle. Bicmos or bipolar processes, the mainstream of pipelined adc design has already.
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