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ADVANCED ANALOG IC DESIGN
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Noise Performance of Elementary Transistor Stages Together with distortion, noise is the main limitation of the performance of analog circuits. It is introduced with simplified expressions for both the MOST and bipolar transistor and applied to the elementary stages with one and two transistors. Also the noise due to parasitic resistances is identified and described. Considerable attention goes to resistive and capacitive noise matching in ultra-low-noise amplifiers. |
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Stability of Operational Amplifiers Multistage operational amplifiers require compensation capacitances for stability. The conditions for stability are discussed for both two-stage and three-stage operational amplifiers. Techniques are given to avoid the positive zero and to realize minimum power consumption at the same time. Several design examples are worked out. |
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Systematic Design of Low-Power Operational Amplifiers For low-power optimization, an operational amplifier can be designed for high speed and stability according to three different design procedures, all leading to the same final result. They will be discussed for a two- and three stage amplifier. The compromises with other specifications such as noise, input and output range will be discussed as well and illustrated for a number of often used configurations. |
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Important Opamp Configurations Long list of opamp configurations is discussed to show which alternative circuit tricks have been used to comply with certain specifications. Considerable design detail is presented on the symmetrical opamp and on the folded cascode. This lecture includes mainly circuit realizations in CMOS but also some in BICMOS technology. |
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Advanced Switched-Capacitor Circuit Design Techniques Switched-capacitor (SC) circuits are used in most analog and mixed-mode CMOS integrated systems. We shall discuss the operation of SC circuits, as well as their basic SC building blocks. Design techniques for SC filters in cascade or multi-feedback (ěladderî) will be described, and various circuit techniques for improved performance discussed. |
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Fully-Differential Operational Amplifiers In mixed-mode design all circuits have to be fully differential. Therefore common-mode feedback amplifiers have to be included to ensure proper biasing and common-mode rejection. They are subject to specifications such as high frequency performance and low power consumption. All possible schematics are reviewed and compared. |
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Offset and CMRR: Random and Systematic Random mismatch between the equally-designed transistors in a differential pair causes offset and reduction of both the CMRR and the PSRR. This phenomenon of random mismatch is discussed in detail. Its relevance is analyzed for differential pairs, current mirrors, etc. It is followed by a number of design guidelines for better matching. |
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Non-ideal Effects in Switched-Capacitor Circuits Non-ideal effects present in SC circuits, including nonzero switch resistance, charge injection; offset, finite gain and bandwidth of the op-amps; as well as leakage and mismatch effects will be analyzed, and effective design techniques for their minimization will be described. |
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Thermal Noise Estimation in Switched-Capacitor Circuits The topics in this lecture will include the theoretical characterization of continuous-time as well as sampled noise; the estimation of thermal noise in CMOS devices, amplifiers, simple SC branches and stages; and noise estimation in multi-stage SC circuits. |
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Distortion in Elementary Transistor Circuits For low supply voltage, a larger fraction of the total supply voltage has to be used, leading to more distortion. The several sources of nonlinear distortion are discussed for MOSTs and bipolar transistor, single-ended and differential. Also the role of feedback is examined in detail. All distortion mechanisms are analyzed in full operational amplifier configurations. |
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Continuous-Time Filters High-frequency filters are usually continuous-time type filters. They are simple in schematic and are able to handle large signals with low distortion. Moreover they need tuning circuits to be able to set the frequency and the quality factor. Most important filter schematics are reviewed and compared for high-frequency capability and power consumption. |
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Micro-Power A/D Converters In medical devices, sensor networks and other applications, power is supplied by batteries or obtained by scavenging. For such applications, the electronic interfaces are only allotted very little power, typically a few microwatts. This lecture provides an overview of micro-power D/A and A/D converter circuits and their design. |
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Bandgap References In this short module, bandgap reference (BGR) fundamentals and the development of CMOS BGRs will be covered. Topics include op-amp based and current-voltage-mirror based BGRs; BGRs with and without output buffers; stability issues arose from negative and positive feedback; loop frequency response and power supply rejection; and startup issues, trimming and design of resistor strings. |