The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform

Jean-michel Redoute - One of the best experts on this subject based on the ideXlab platform.

  • susceptibility of Operational Amplifiers to conducted emi injected through the ground plane into their output terminal
    IEEE Transactions on Reliability, 2016
    Co-Authors: Anna Richelli, Marco Grassi, Giovanni Delaini, Jean-michel Redoute
    Abstract:

    In practical printed circuit board (PCB) designs, electromagnetic interference (EMI) is coupled from the ground plane, which is commonly shared among the analog, digital, and mixed-signal integrated circuits. This noisy ground plane couples interference capacitively to all the IC pins, including the output: this effect is exacerbated when the IC is connected to long wires and traces that are routed close to the conductive ground plane. This paper reports on the effect of interference, which is coupled capacitively from the PCB ground plane into all the IC pins of an opamp connected as a voltage buffer. Simulations illustrate the susceptibilities in custom Operational amplifier designs, and are corroborated by measurements on several commercial devices. These measurements show that the EMI-induced offset can attain considerable values for the most critical EMI frequencies, which lie between 10 and 100 MHz. Moreover, these illustrate that there is a considerable susceptibility of Operational Amplifiers to electromagnetic interference coupled to their output pins.

  • Increased EMI immunity in CMOS Operational Amplifiers using an integrated common-mode cancellation circuit
    2015 IEEE International Symposium on Electromagnetic Compatibility (EMC), 2015
    Co-Authors: Marco Grassi, Jean-michel Redoute, Anna Richelli
    Abstract:

    This paper presents an on-chip common-mode cancellation circuit which increases the immunity to electromagnetic interference (EMI) of integrated CMOS Operational Amplifiers when EMI is injected into their inputs. The circuits have been designed in the UMC 180nm CMOS technology. Two case studies have been considered: first, the common-mode cancellation circuit has been used in a Miller amplifier and secondly, in a folded cascode opamp topology. Circuit simulations and mathematical derivations illustrate how the proposed common-mode cancellation input stage strongly reduces the EMI susceptibility of both opamps, even in the presence of large amplitude interferences. The output offset voltages which are obtained when EMI amplitudes up to 3.3 V pp are injected in the noninverting inputs of the proposed Amplifiers when these are connected in a voltage follower configuration, are reduced by nearly one order of magnitude.

  • Increasing the EMI immunity of CMOS Operational Amplifiers using an on-chip common-mode cancellation circuit
    2014 International Symposium on Electromagnetic Compatibility, 2014
    Co-Authors: Anna Richelli, Jean-michel Redoute
    Abstract:

    This paper presents an on-chip common-mode cancellation circuit which increases the common-mode rejection ratio (CMRR) in Operational Amplifiers, while at the same time increasing their immunity to electromagnetic interference (EMI). This common-mode cancellation circuit can be designed so as to double the differential gain while significantly reducing the common-mode gain. Simulations illustrate how the proposed amplifier exhibits an increased immunity to EMI injected in the opamp's inputs. A case study example shows that the maximum output offset voltage which is obtained when an EMI amplitude of 1 V pp is injected in the noninverting input of a Miller amplifier connected as a voltage follower is equal to 50 mV and 200 mV with and without the common-mode cancellation structure respectively. Finally, simulations show that the common-mode deleting circuit is not overly sensitive to mismatch.

Anna Richelli - One of the best experts on this subject based on the ideXlab platform.

  • susceptibility of Operational Amplifiers to conducted emi injected through the ground plane into their output terminal
    IEEE Transactions on Reliability, 2016
    Co-Authors: Anna Richelli, Marco Grassi, Giovanni Delaini, Jean-michel Redoute
    Abstract:

    In practical printed circuit board (PCB) designs, electromagnetic interference (EMI) is coupled from the ground plane, which is commonly shared among the analog, digital, and mixed-signal integrated circuits. This noisy ground plane couples interference capacitively to all the IC pins, including the output: this effect is exacerbated when the IC is connected to long wires and traces that are routed close to the conductive ground plane. This paper reports on the effect of interference, which is coupled capacitively from the PCB ground plane into all the IC pins of an opamp connected as a voltage buffer. Simulations illustrate the susceptibilities in custom Operational amplifier designs, and are corroborated by measurements on several commercial devices. These measurements show that the EMI-induced offset can attain considerable values for the most critical EMI frequencies, which lie between 10 and 100 MHz. Moreover, these illustrate that there is a considerable susceptibility of Operational Amplifiers to electromagnetic interference coupled to their output pins.

  • Increased EMI immunity in CMOS Operational Amplifiers using an integrated common-mode cancellation circuit
    2015 IEEE International Symposium on Electromagnetic Compatibility (EMC), 2015
    Co-Authors: Marco Grassi, Jean-michel Redoute, Anna Richelli
    Abstract:

    This paper presents an on-chip common-mode cancellation circuit which increases the immunity to electromagnetic interference (EMI) of integrated CMOS Operational Amplifiers when EMI is injected into their inputs. The circuits have been designed in the UMC 180nm CMOS technology. Two case studies have been considered: first, the common-mode cancellation circuit has been used in a Miller amplifier and secondly, in a folded cascode opamp topology. Circuit simulations and mathematical derivations illustrate how the proposed common-mode cancellation input stage strongly reduces the EMI susceptibility of both opamps, even in the presence of large amplitude interferences. The output offset voltages which are obtained when EMI amplitudes up to 3.3 V pp are injected in the noninverting inputs of the proposed Amplifiers when these are connected in a voltage follower configuration, are reduced by nearly one order of magnitude.

  • Increasing the EMI immunity of CMOS Operational Amplifiers using an on-chip common-mode cancellation circuit
    2014 International Symposium on Electromagnetic Compatibility, 2014
    Co-Authors: Anna Richelli, Jean-michel Redoute
    Abstract:

    This paper presents an on-chip common-mode cancellation circuit which increases the common-mode rejection ratio (CMRR) in Operational Amplifiers, while at the same time increasing their immunity to electromagnetic interference (EMI). This common-mode cancellation circuit can be designed so as to double the differential gain while significantly reducing the common-mode gain. Simulations illustrate how the proposed amplifier exhibits an increased immunity to EMI injected in the opamp's inputs. A case study example shows that the maximum output offset voltage which is obtained when an EMI amplitude of 1 V pp is injected in the noninverting input of a Miller amplifier connected as a voltage follower is equal to 50 mV and 200 mV with and without the common-mode cancellation structure respectively. Finally, simulations show that the common-mode deleting circuit is not overly sensitive to mismatch.

J H Huijsing - One of the best experts on this subject based on the ideXlab platform.

  • capacitively coupled chopper Operational Amplifiers
    2017
    Co-Authors: Qinwen Fan, Kofi A A Makinwa, J H Huijsing
    Abstract:

    In Chap. 3, the basic capacitively-coupled chopper topology for Operational Amplifiers (opamp) has been described. In this chapter, two capacitively-coupled chopper opamps (CCOPA) will be presented. They both achieve wide input common-mode voltage range (CMVR) and high precision. The first opamp employs a single-path architecture and features high power efficiency and simplicity. The second opamp is more complex and employs a multipath architecture. Thus, it is less power efficient, but has a wider bandwidth and a smoother transfer function.

  • dynamic offset cancellation techniques for Operational Amplifiers
    2013
    Co-Authors: J H Huijsing, Kofi A A Makinwa
    Abstract:

    At low frequencies, offset, 1/f noise and drift are the dominant error sources of Operational Amplifiers. This is especially true in CMOS technology. This chapter reviews precision techniques that can be used to achieve low 1/f noise and low offset in Operational Amplifiers.

  • fully differential Operational Amplifiers
    2011
    Co-Authors: J H Huijsing
    Abstract:

    As the supply and signal voltages go down to lower values from 30, 12, 5, 3, 2, and finally 1 V, the signal-to-noise-and-interference ratio becomes increasingly worse. An important way to cope with this problem is to use fully differential signal paths. The differential peak-to-peak signal then becomes maximally twice the total supply voltage V S = V SP − V SN . But even more important will be that the influence of substrate interference on the two balanced signals will largely cancel one another. All kinds of Amplifiers, filters, sigma-delta converters, and other circuits using fully differential OpAmps may thus be designed in a fully balanced or differential way. In this chapter several practical design examples of fully differential Operational Amplifiers are presented.

  • Operational Amplifiers theory and design
    2000
    Co-Authors: J H Huijsing
    Abstract:

    Operational Amplifiers Theory and Design, Second Edition presents a systematic circuit design of Operational Amplifiers. Containing state-of-the-art material as well as the essentials, the book is written to appeal to both the circuit designer and the system designer. It is shown that the topology of all Operational Amplifiers can be divided into nine main overall configurations. These configurations range from one gain stage up to four or more stages. Many famous designs are evaluated in depth.Additional chapters included are on systematic design of V-offset Operational Amplifiers and precision instrumentation Amplifiers by applying chopping, auto-zeroing, and dynamic element-matching techniques. Also, techniques for frequency compensation of Amplifiers with high capacitive loads have been added.Operational Amplifiers Theory and Design, Second Edition presents high-frequency compensation techniques to HF-stabilize all nine configurations. Special emphasis is placed on low-power low-voltage architectures with rail-to-rail input and output ranges.In addition to presenting characterization of Operational Amplifiers by macro models and error matrices, together with measurement techniques for their parameters it also develops the design of fully differential Operational Amplifiers and Operational floating Amplifiers.Operational Amplifiers Theory and Design, Second Edition is carefully structured and enriched by numerous figures, problems and simulation exercises and is ideal for the purpose of self-study and self-evaluation.

  • frequency compensation techniques for low power Operational Amplifiers
    1995
    Co-Authors: Rudy G H Eschauzier, J H Huijsing
    Abstract:

    Preface. List of Symbols. 1: Introduction. 2: Properties of Feedback Circuits. 3: Stability of Feedback Circuits. 4: Basic Frequency Compensation of Integrated Circuits. 5: Multistage Compensation Techniques. 6: Multipath Compensation Techniques. 7: Realizations. Bibliography.

M. Ismail - One of the best experts on this subject based on the ideXlab platform.

  • Robust design of rail-to-rail CMOS Operational Amplifiers for a low power supply voltage
    IEEE Journal of Solid-State Circuits, 1996
    Co-Authors: S. Sakurai, M. Ismail
    Abstract:

    New bias circuits which provide currents to n- and p-channel differential pairs placed in parallel are introduced. The bias currents are a function of the input common mode voltage in such a way that the total transconductance, g/sub mT/, of the differential pairs is constant over the entire common mode range. The bias circuits, together with the differential pairs, are used to design input stages of low-voltage (/spl les/3.3 V) complementary metal-oxide-semiconductor (CMOS) Operational Amplifiers (op amps). The new circuits are robust in that they do not require transconductance parameter matching of n- and p-channel transistors for proper operation. A simple rail-to-rail common source output stage with class AB control is also developed and used in the design of two-stage op amps. Experimental results of MOSIS test chips containing a family of low-voltage op amps fabricated in 2 /spl mu/m p-well process are provided. The results demonstrate the effectiveness and robustness of the proposed constant transconductance input stages in achieving constant opamp unity gain frequency with very low levels of total harmonic distortion (THD) and with 3.3 V and 2.5 V power supply voltage.

J. Francisco Duque-carrillo - One of the best experts on this subject based on the ideXlab platform.

  • 1-V rail-to-rail Operational Amplifiers in standard CMOS technology
    IEEE Journal of Solid-State Circuits, 2000
    Co-Authors: J. Francisco Duque-carrillo, Juan Miguel Valverde, José L. Ausín, Guido Torelli, Miguel A. Dominguez
    Abstract:

    The constraints on the design of CMOS Operational Amplifiers with rail-to-rail input range for extremely low supply voltage operation, are addressed. Two design approaches for Amplifiers based on complementary input differential pairs and a single input pair, respectively, are presented. The first realizes a feedforward action to accommodate the common-mode (CM) component of the input signals to the amplifier input range. The second approach performs a negative feedback action over the input CM signal. Two Operational Amplifiers based on the proposed approaches have been designed for 1-V total supply operation, and fabricated in a standard 1.2-/spl mu/m CMOS process. Experimental results are provided and the corresponding performances are discussed and compared.

  • Biasing circuit for high input swing Operational Amplifiers
    IEEE Journal of Solid-State Circuits, 1995
    Co-Authors: J. Francisco Duque-carrillo, R. Perez-aloe, J.m. Valverde
    Abstract:

    This paper introduces a biasing scheme that overcomes the inherent drawbacks associated with high input common-mode range (CMR) Amplifiers: nonconstant transconductance (G/sub m/) and very poor common-mode rejection ratio (CMRR). The proposed circuit achieves a constant amplifier G/sub m/ by maintaining a constant sum of the square-roots of the bias currents of the complementary input pairs, while the high rejection to input common-mode signals is achieved by making a gradual transition between these currents as function of the input common-mode component (V/sub m, cm/). Experimental results obtained from a CMOS n-well 2 /spl mu/m chip prototype with 5 V of total supply voltage, show a maximum transconductance deviation less than 5% from its value for a common-mode input voltage at midsupply, as well as a CMRR improvement of 12 dB with respect to the classical biasing scheme. Other representative figures of its experimental behavior are also given.