An Offset Cancelation Technique for Latch Type Sense Amplifiers

An offset compensation technique for a latch type sense amplifier is proposed in this paper. The proposed scheme is based on the recalibration of the charging/discharging current of the critical nodes which are affected by the device mismatches. The circuit has been designed in a 65 nm CMOS technology with 1.2 V core transistors. The auto-calibration procedure is fully digital. Simulation results are given verifying the operation for sampling a 5 Gb/s signal dissipating only 360 uW

펄스 기반 피드 포워드 이퀄라이저를 갖춘 고용량 DRAM을 위한 컨트롤러 PHY 설계

학위논문 (박사) -- 서울대학교 대학원 : 공과대학 전기·정보공학부, 2020. 8. 김수환.A controller PHY for managed DRAM solution, which is a new memory structure to maximize capacity while minimizing refresh power, is presented. Inter-symbol interference is critical in such a high-capacity DRAM interface in which many DRAM chips share a command/address (C/A) channel. A pulse-based feed-forward equalizer (PB-FFE) is introduced to reduce ISI on a C/A channel. The controller PHY supports all the training sequences specified in the DDR4 standard. A glitch-free DCDL is also adopted to perform link training efficiently and to reduce training time. The DQ transmitter adopts quarter-rate architecture to reduce output latency. For the quarter-rate transmitters in DQ, we propose a quadrature error corrector (QEC), in which clock signal phase errors are corrected using two replicas of the 4:1 serializer of the output stage. Pulse shrinking is used to compare and equalize the outputs of these two replica serializers. A controller PHY was fabricated in 55nm CMOS. The PB-FFE increases the timing margin from 0.23UI to 0.29UI at 1067Mbps. At 2133Mbps, the read timing and voltage margins are 0.53UI and 211mV after read training, and the write margins are 0.72UI and 230mV after write training. To validate the QEC effectiveness, a prototype quarter-rate transmitter, including the QEC, was fabricated to another chip in 65nm CMOS. Adopting our QEC, the experimental results show that the output phase errors of the transmitter are reduced to a residual error of 0.8ps, and the output eye width and height are improved by 84% and 61%, respectively, at a data-rate of 12.8Gbps.본 연구에서 용량을 최대화하면서도 리프레시 전력을 최소화할 수 있는 새로운 메모리 구조인 관리형 DRAM 솔루션을 위한 컨트롤러 PHY를 제시하였다. 이와 같은 고용량 DRAM 인터페이스에서는 많은 DRAM 칩이 명령 / 주소 (C/A) 채널을 공유하고 있어서 심볼 간 간섭이 발생한다. 본 연구에서는 이러한 C/A 채널에서의 심볼 간 간섭을 줄이기 위해 펄스 기반 피드 포워드 이퀄라이저 (PB-FFE)를 채택하였다. 또한 본 연구의 컨트롤러 PHY는 DDR4 표준에 지정된 모든 트레이닝 시퀀스를 지원한다. 링크 트레이닝을 효율적으로 수행하고 트레이닝 시간을 줄이기 위해 글리치가 발생하지 않는 디지털 제어 지연 라인 (DCDL)을 채택하였다. 컨트롤러 PHY의 DQ 송신기는 출력 대기 시간을 줄이기 위해 쿼터 레이트 구조를 채택하였다. 쿼터 레이트 송신기의 경우에는 직교 클럭 간 위상 오류가 출력 신호의 무결성에 영향을 주게 된다. 이러한 영향을 최소화하기 위해 본 연구에서는 출력 단의 4 : 1 직렬 변환기의 두 복제본을 사용하여 클록 신호 위상 오류를 수정하는 QEC (Quadrature Error Corrector)를 제안하였다. 복제된 2개의 직렬 변환기의 출력을 비교하고 균등화하기 위해 펄스 수축 지연 라인이 사용되었다. 컨트롤러 PHY는 55nm CMOS 공정으로 제조되었다. PB-FFE는 1067Mbps에서 C/A 채널 타이밍 마진을 0.23UI에서 0.29UI로 증가시킨다. 읽기 트레이닝 후 읽기 타이밍 및 전압 마진은 2133Mbps에서 0.53UI 및 211mV이고, 쓰기 트레이닝 후 쓰기 마진은 0.72UI 및 230mV이다. QEC의 효과를 검증하기 위해 QEC를 포함한 프로토 타입 쿼터 레이트 송신기를 65nm CMOS의 다른 칩으로 제작하였다. QEC를 적용한 실험 결과, 송신기의 출력 위상 오류가 0.8ps의 잔류 오류로 감소하고, 출력 데이터 눈의 폭과 높이가 12.8Gbps의 데이터 속도에서 각각 84 %와 61 % 개선되었음을 보여준다.CHAPTER 1 INTRODUCTION 1 1.1 MOTIVATION 1 1.1.1 HEAVY LOAD C/A CHANNEL 5 1.1.2 QUARTER-RATE ARCHITECTURE IN DQ TRANSMITTER 7 1.1.3 SUMMARY 8 1.2 THESIS ORGANIZATION 10 CHAPTER 2 ARCHITECTURE 11 2.1 MDS DIMM STRUCTURE 11 2.2 MDS CONTROLLER 15 2.3 MDS CONTROLLER PHY 17 2.3.1 INITIALIZATION SEQUENCE 20 2.3.2 LINK TRAINING FINITE-STATE MACHINE 23 2.3.3 POWER DOWN MODE 28 CHAPTER 3 PULSE-BASED FEED-FORWARD EQUALIZER 29 3.1 COMMAND/ADDRESS CHANNEL 29 3.2 COMMAND/ADDRESS TRANSMITTER 33 3.3 PULSE-BASED FEED-FORWARD EQUALIZER 35 CHAPTER 4 CIRCUIT IMPLEMENTATION 39 4.1 BUILDING BLOCKS 39 4.1.1 ALL-DIGITAL PHASE-LOCKED LOOP (ADPLL) 39 4.1.2 ALL-DIGITAL DELAY-LOCKED LOOP (ADDLL) 44 4.1.3 GLITCH-FREE DCDL CONTROL 47 4.1.4 DUTY-CYCLE CORRECTOR (DCC) 50 4.1.5 DQ/DQS TRANSMITTER 52 4.1.6 DQ/DQS RECEIVER 54 4.1.7 ZQ CALIBRATION 56 4.2 MODELING AND VERIFICATION OF LINK TRAINING 59 4.3 BUILT-IN SELF-TEST CIRCUITS 66 CHAPTER 5 QUADRATURE ERROR CORRECTOR USING REPLICA SERIALIZERS AND PULSE-SHRINKING DELAY LINES 69 5.1 PHASE CORRECTION USING REPLICA SERIALIZERS AND PULSE-SHRINKING UNITS 69 5.2 OVERALL QEC ARCHITECTURE AND ITS OPERATION 71 5.3 FINE DELAY UNIT IN THE PSDL 76 CHAPTER 6 EXPERIMENTAL RESULTS 78 6.1 CONTROLLER PHY 78 6.2 PROTOTYPE QEC 88 CHAPTER 7 CONCLUSION 94 BIBLIOGRAPHY 96Docto

Exploration and Design of High Performance Variation Tolerant On-Chip Interconnects

Siirretty Doriast

An Energy-Efficient Reconfigurable Mobile Memory Interface for Computing Systems

The critical need for higher power efficiency and bandwidth transceiver design has significantly increased as mobile devices, such as smart phones, laptops, tablets, and ultra-portable personal digital assistants continue to be constructed using heterogeneous intellectual properties such as central processing units (CPUs), graphics processing units (GPUs), digital signal processors, dynamic random-access memories (DRAMs), sensors, and graphics/image processing units and to have enhanced graphic computing and video processing capabilities. However, the current mobile interface technologies which support CPU to memory communication (e.g. baseband-only signaling) have critical limitations, particularly super-linear energy consumption, limited bandwidth, and non-reconfigurable data access. As a consequence, there is a critical need to improve both energy efficiency and bandwidth for future mobile devices.;The primary goal of this study is to design an energy-efficient reconfigurable mobile memory interface for mobile computing systems in order to dramatically enhance the circuit and system bandwidth and power efficiency. The proposed energy efficient mobile memory interface which utilizes an advanced base-band (BB) signaling and a RF-band signaling is capable of simultaneous bi-directional communication and reconfigurable data access. It also increases power efficiency and bandwidth between mobile CPUs and memory subsystems on a single-ended shared transmission line. Moreover, due to multiple data communication on a single-ended shared transmission line, the number of transmission lines between mobile CPU and memories is considerably reduced, resulting in significant technological innovations, (e.g. more compact devices and low cost packaging to mobile communication interface) and establishing the principles and feasibility of technologies for future mobile system applications. The operation and performance of the proposed transceiver are analyzed and its circuit implementation is discussed in details. A chip prototype of the transceiver was implemented in a 65nm CMOS process technology. In the measurement, the transceiver exhibits higher aggregate data throughput and better energy efficiency compared to prior works

Analog/RF Circuit Design Techniques for Nanometerscale IC Technologies

CMOS evolution introduces several problems in analog design. Gate-leakage mismatch exceeds conventional matching tolerances requiring active cancellation techniques or alternative architectures. One strategy to deal with the use of lower supply voltages is to operate critical parts at higher supply voltages, by exploiting combinations of thin- and thick-oxide transistors. Alternatively, low voltage circuit techniques are successfully developed. In order to benefit from nanometer scale CMOS technology, more functionality is shifted to the digital domain, including parts of the RF circuits. At the same time, analog control for digital and digital control for analog emerges to deal with current and upcoming imperfections

CMOS Data Converters for Closed-Loop mmWave Transmitters

With the increased amount of data consumed in mobile communication systems, new solutions for the infrastructure are needed. Massive multiple input multiple output (MIMO) is seen as a key enabler for providing this increased capacity. With the use of a large number of transmitters, the cost of each transmitter must be low. Closed-loop transmitters, featuring high-speed data converters is a promising option for achieving this reduced unit cost.In this thesis, both digital-to-analog (D/A) and analog-to-digital (A/D) converters suitable for wideband operation in millimeter wave (mmWave) massive MIMO transmitters are demonstrated. A 2 76 bit radio frequency digital-to-analog converter (RF-DAC)-based in-phase quadrature (IQ) modulator is demonstrated as a compact building block, that to a large extent realizes the transmit path in a closed-loop mmWave transmitter. The evaluation of an successive-approximation register (SAR) analog-to-digital converter (ADC) is also presented in this thesis. Methods for connecting simulated and measured performance has been studied in order to achieve a better understanding about the alternating comparator topology.These contributions show great potential for enabling closed-loop mmWave transmitters for massive MIMO transmitter realizations

Preliminary candidate advanced avionics system for general aviation

An integrated avionics system design was carried out to the level which indicates subsystem function, and the methods of overall system integration. Sufficient detail was included to allow identification of possible system component technologies, and to perform reliability, modularity, maintainability, cost, and risk analysis upon the system design. Retrofit to older aircraft, availability of this system to the single engine two place aircraft, was considered