Operational Amplifier Noise

Operational Amplifier Noise

Techniques and Tips for Analyzing and Reducing Noise

1st Edition - January 13, 2012

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  • Author: Art Kay
  • Hardcover ISBN: 9780750685252
  • eBook ISBN: 9780080942438

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Arthur Kay’s exciting new publication is a must have for practicing, professional electrical engineers. This comprehensive guide shows engineers how to design amplifiers and associated electronics to minimize noise, providing tricks, rules-of-thumb, and analysis to create successful low noise circuits. Forget the classical textbook traps of equations, virtual grounds, and a lot of double-speak, the novel but educational presentation used here uses definition-by -example and straight-forward analysis. This is the ultimate reference book for engineers who don't have the time to read, since the concepts are presented in detailed pictures and then repeated in the text for those who like both. Operational amplifiers play a vital role in modern electronics design. Today, op amps serve as the interfaces between the digital world of microprocessors, microcontrollers, and other digital circuits and the analog "real world". If an analog signal must be amplified, conditioned, filtered, or converted to be used by a digital system, an op amp is almost always involved. Noise is an unwanted signal that will corrupt or distort the desired signal, and veteran engineers as well as new college graduates are often faced with a lack of experience in noise analysis for operational amplifiers. The author has created a publication that is packed with essential information, while still being accessible to all readers.

Key Features

  • Clear, definition-by-example presentation allows for immediate use of techniques introduced
  • Tricks and rules-of-thumb, derived from author's decades of experience
  • Extreme use of figures for rapid absorption of concepts
  • Concise text explains the key points in all figures
  • Accessible to all types of readers
  • Analysis and design of low-noise circuits using op amps, including design tradeoffs for low-noise
  • Desktop reference for designing low-noise op amp circuits for novice to experienced engineers
  • Accurate measurement and prediction of intrinsic noise levels, using analysis by hand and SPICE simulation


Practicing, professional electrical engineers, specifically analog design engineers, circuit designers, test engineers, applications engineers, or field applications engineers

Table of Contents

  • Preface


    Chapter 1. Introduction and Review of Statistics

    1.1 Time Domain View of Noise

    1.2 Statistical View of Noise

    1.3 Frequency Domain View of Noise

    1.4 Converting Spectral Density to RMS Noise

    Chapter Summary


    Further Reading

    Chapter 2. Introduction to Op-Amp Noise

    2.1 Op-Amp Noise Analysis Technique

    2.2 Introducing the Op-Amp Noise Model

    2.3 Noise Bandwidth

    2.4 Broadband RMS Noise Calculation

    2.5 1/f RMS Noise Calculation

    2.6 Combining Flicker and Broadband Noise

    2.7 Noise Model for Example Circuit

    2.8 Noise Gain

    2.9 Converting Current Noise to Voltage Noise

    2.10 Including the Effect of Thermal Noise

    2.11 Combining All the Noise Sources and Computing Peak-to-Peak Output Noise

    2.12 Derivation of Key Noise Formulas

    Chapter Summary


    Further Reading

    Chapter 3. Op-Amp Noise Example Calculations

    3.1 Example Calculation #1: OPA627 Noninverting Amplifier

    3.2 Compute the Noise Bandwidth

    3.3 Get Key Noise Specifications from the Data Sheet

    3.4 Compute Total Op-Amp Voltage Noise Contribution

    3.5 Compute Total Thermal Noise Contribution

    3.6 Combine All the Noise Sources and Compute Peak-to-Peak Output

    3.7 Example Calculation #2: Two-Stage Amplifier

    Chapter Summary


    Further Reading

    Chapter 4. Introduction to Spice Noise Analysis

    4.1 Running a Noise Analysis in TINA Spice

    4.2 Test the Op-Amp Model Noise Accuracy

    4.3 Build Your Own Noise Model

    4.4 Use TINA to Analyze the Circuit Given in Chapter 3

    4.5 Feedback Capacitor Simulation Example

    Chapter Summary


    Further Reading

    Chapter 5. Introduction to Noise Measurement

    5.1 Equipment for Measuring Noise: True RMS DMM

    5.2 Equipment for Measuring Noise: Oscilloscope

    5.3 Equipment for Measuring Noise: Spectrum Analyzer

    5.4 Shielding

    5.5 Verify the Noise Floor

    5.6 Account for the Noise Floor

    5.7 Measure Example Circuit #1 Using a True RMS Meter

    5.8 Measure Example Circuit #1 Using an Oscilloscope

    5.9 Measure Example Circuit #1 Using a Spectrum Analyzer

    5.10 Measure Low Frequency Noise for the OPA227

    5.11 Offset Temperature Drift vs. 1/f Noise in Low-Frequency Noise Measurement

    Chapter Summary


    Further Reading

    Chapter 6. Noise Inside the Amplifier

    6.1 Five Rules of Thumb for Worst-Case Noise Analysis and Design

    6.2 Detailed Mathematics for Bipolar Noise

    6.3 Detailed Mathematics for FET Noise

    6.4 Simplified Physical Connection Inside Amplifier

    Chapter Summary


    Further Reading

    Chapter 7. Popcorn Noise

    7.1 Review of 1/f and Broadband Noise

    7.2 What Is Popcorn Noise

    7.3 What Causes Popcorn Noise?

    7.4 How Common Is the Problem?

    7.5 Popcorn Noise—Current or Voltage Noise?

    7.6 Bench and Production Test for Voltage Popcorn Noise

    7.7 Bench and Production Test for Current Popcorn Noise

    7.8 Analyzing the Popcorn Noise Data

    7.9 Setting Limits to a Popcorn Noise Test

    7.10 When Is Popcorn Noise a Concern?

    Chapter Summary


    Further Reading

    Chapter 8. 1/f Noise and Zero-Drift Amplifiers

    8.1 Zero-Drift Amplifiers

    8.2 Zero-Drift Amplifier Spectral Density Curve

    8.3 Low-Frequency Noise

    8.4 Measuring Low-Frequency Noise

    Chapter Summary


    Further Reading

    Chapter 9. Instrumentation Amplifier Noise

    9.1 Short Review of Three Amp Instrumentation Amplifier

    9.2 Noise Model of Three Amp Instrumentation Amplifier

    9.3 Hand Analysis of Three Amp Instrumentation Amplifier

    9.4 Simulation of Three Amp Instrumentation Amplifier

    9.5 Reducing Noise with Averaging Circuit

    Chapter Summary


    Further Reading

    Chapter 10. Photodiode Amplifier Noise

    10.1 Introduction to Photodiodes

    10.2 The Simple Transimpedance Amplifier

    10.3 Photodiode Current Noise

    10.4 Thermal Noise from Rf

    10.5 Noise from Op-amp Voltage Noise Source

    10.6 Total Noise (Op-amp, Diode, and Resistance)

    10.7 Stability of Transimpedance Amplifier

    Chapter Summary


    Further Reading

    Chapter 11. Photodiode Noise Amplifier Example Results

    11.1 Photodiode Example Specifications

    11.2 Photodiode Current Noise Calculations

    11.3 Op-amp Specifications

    11.4 Op-amp Voltage Noise Calculations

    11.5 Thermal (Resistor) Noise Calculations

    11.6 Op-amp Current Noise Calculations

    11.7 Total Noise for Example Transimpedance Amplifier

    11.8 Spice Analysis of Example Circuit

    11.9 Measuring the Noise for the Example Transimpedance Amplifier

    Chapter Summary


    Further Reading


    Answers to Questions


Product details

  • No. of pages: 248
  • Language: English
  • Copyright: © Newnes 2012
  • Published: January 13, 2012
  • Imprint: Newnes
  • Hardcover ISBN: 9780750685252
  • eBook ISBN: 9780080942438

About the Author

Art Kay

Affiliations and Expertise

Texas Instruments, Tucson, AZ, USA

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  • MikaLeppanen Mon Jan 07 2019

    Noise calculations

    Noise calculations