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Mixed-Signal VLSI Design Course Code: EE719 Department: Electrical - - PowerPoint PPT Presentation
Mixed-Signal VLSI Design Course Code: EE719 Department: Electrical - - PowerPoint PPT Presentation
Mixed-Signal VLSI Design Course Code: EE719 Department: Electrical Engineering Lecture 14: February 05, 2018 Instructor Name: M. Shojaei Baghini E-Mail ID: mshojaei@ee.iitb.ac.in 1 2 2 Module 18 Sample & Hold Circuit with Buffer
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IIT-Bombay Lecture 14 M. Shojaei Baghini
Unity Gain Sampling with Buffer
- Advantage of op-amp
- Sensitive to charge injection
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IIT-Bombay Lecture 14 M. Shojaei Baghini
Unity Gain Sample & Hold Circuit with Buffer and Switching at Node X
- 1. S2 turns off.
- 2. S1 turns off.
- 3. S3 turns on.
What about the order for the next phase? How do you compare your answer with the example given in Razavi’s book chapter? Flip Around T&H
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IIT-Bombay Lecture 14 M. Shojaei Baghini
Sample Hold Unity Gain Sample & Hold Circuit with Buffer and Switching at Node X
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IIT-Bombay Lecture 14 M. Shojaei Baghini
Discrete Time Unity Gain Sampler with Switching at Node X
Notice: Insensitive Circuit with Respect to the Injected Charge from S1 and Stray Capacitor at Node X
(I) (III) (II)
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+ Why is the circuit insensitive to Δq1?
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IIT-Bombay Lecture 14 M. Shojaei Baghini
Differential Architecture: No Differential-mode Charge Injection from S2 to CH Seq turns off slightly after S2 and S2’, and, before S1 and S1’.
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IIT-Bombay Lecture 14 M. Shojaei Baghini
Module 19 Introduction to Discrete Time Amplifiers
Reference Chapter: Introduction to Switched capacitor Circuits Design of Analog CMOS Integrated Circuits, by Behzad Razavi Second edition, 2017
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IIT-Bombay Lecture 14 M. Shojaei Baghini
Discrete Time Amplifier - Introduction
- Continuous time operation
- No DC loading
- No resistive element and hence no RC variation issue.
- Potential to be converted to a track & hold circuit
- Advantage of using op-amp?
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IIT-Bombay Lecture 14 M. Shojaei Baghini
Discrete Time Amplifier (Embedded T&H ) with Bottom Plate Switching - Example
S1 and S2 are closed: Sample S3 is closed: Amplify and Hold
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IIT-Bombay Lecture 14 M. Shojaei Baghini
Discrete Time Amplifier (Embedded T&H ) with Bottom Plate Switching – No Effect of Charge Injection from S1
(due to charge injection)
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