operational amplifiers digital simulation nate moehring
TRANSCRIPT
![Page 1: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/1.jpg)
Operational AmplifiersDigital Simulation
Nate Moehring
![Page 2: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/2.jpg)
Operational Amplifiers
• Used in amplifiers, attenuators, and filters
• Ideal Properties of an Op Amp:• Infinite open-loop gain, Aol = infinity
• Infinite input impedance, Rin = infinity
• Zero output impedance, Rout = 0
• Zero noise contribution
• Zero DC output offset
• Infinite bandwidth, infinite frequency response
• Both differential inputs stick together
![Page 3: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/3.jpg)
Why use op amps?
• Extremely high gain (10,000x)
• Infinite input resistance good for adding multiple sources (0 current = 0 voltage drop)
• Develop high pole filters
![Page 4: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/4.jpg)
Example
• Passive Band Pass
![Page 5: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/5.jpg)
Example
• Active Band Pass
![Page 6: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/6.jpg)
Example
• Active Band Pass w/ amplifier
![Page 7: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/7.jpg)
Op Amp configurations
• Rails +/- to higher input
• (Takes difference
• Multiplies by 10,000)
Comparator
![Page 8: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/8.jpg)
Op Amp configurations
• Vo = -Vi(Rf/Ri)
• (Feedback loop creates
180o out of phase signal
that eliminates large Aol)
Inverting Gain
![Page 9: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/9.jpg)
Op Amp configurations
• Vo = Vi(1 + Rf/Ri)
• (Feedback line
must always go to negative
input. Otherwise, we
would be summing infinitely.)
Non - Inverting Gain
![Page 10: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/10.jpg)
Op Amp configurations
• Vo = Vi(1 + 0/) = 1
• Also called “follow me”
amplifier.
Buffer – Isolation Amplifier
![Page 11: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/11.jpg)
Op Amp configurations
• fc = 1/(2RC)
• “Active”, although this
filter is no better than a
passive filter.
Filter
![Page 12: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/12.jpg)
Op Amp configurationsDifferential Amplifier
• Vo = R2/R1(V2-V1)
• “Subtractor”
![Page 13: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/13.jpg)
Op Amp configurationsSumming Amplifier
• Vo = V1(R3/R1) + V2(R3/R2)
• “Adder”
![Page 14: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/14.jpg)
Parametric resultsw/ transient
![Page 15: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/15.jpg)
Parametric resultsw/ AC Sweep
![Page 16: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/16.jpg)
TransistorsBipolar Junction Transistors BJT (npn)
• Uses a small amount of current to allow a large amount of current to pass through it. (Amplifier) (Flood gate)
• Also used as “on/off” switch. (Transistor Transistor Logic (TTL))
• Bipolar.olb
Base
Collector
Emitter
![Page 17: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/17.jpg)
NOT Gate
These TTL representations are
greatly simplified for logical interpretation and are not meant for
actual implementation as seen here.
![Page 18: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/18.jpg)
AND Gate
![Page 19: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/19.jpg)
OR Gate
![Page 20: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/20.jpg)
Digital Simulation
• Use Bias Point calculations manually changing VDCs
• Use Bussed STIM sources to perform transient analysis.
• Get digital components from 74ac (pro) or Eval library (student)
![Page 21: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/21.jpg)
Using STIM sources
• Use STIM4 from source library• Draw bus wire• Place “Net Alias” ON bus, ie. A[0:3]• Use “Bus Entry” tool to extract lines• Name lines using Place “Net Alias”• Double click STIM4 to create pattern• Probe input and outputs• Run transient simulation
![Page 22: Operational Amplifiers Digital Simulation Nate Moehring](https://reader035.vdocuments.net/reader035/viewer/2022062511/5519b82d5503465b578b4894/html5/thumbnails/22.jpg)
Voter Problem
• Build using 74xx logic gates
• Input manually using VDC sources and view outputs using Bias Voltages
• Input using STIM4 providing all possible input combinations.