Embedded Systems Operational Amplifiers

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Embedded SystemsOperational Amplifiers
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OpAmps
very high gain dc-coupled differential
amplifiers with single-ended outputs
offset null
NC
24 transistors 11 resistors 1
capacitor amplifier gains 105-106
invert
15V
non-invert
out
offset null
-15V
about 0.60 a piece
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OpAmps
a few millivolts difference between inputs will
cause the output to swing full range

1. output swings dramatically and via feedback,
   makes difference between the inputs go to zero
2. inputs draw no current (10-9A)

-15V
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OpAmps
What does it mean to say the op amp is stable?
V
Vout K (V - V-)
V-
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OpAmps
What does it mean to say the op amp is stable?
stable or unstable?
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OpAmps - Negative Feedback
feedback - comparing the output of a system to
the desired output in order to make a signed
corrective action
CYBERNETICS
negative feedback - connect the output back to
the input in such a way as to cancel some of the
input.
Harold S. Black - patent application on
negative feedback in 1928 was treated in the
same manner as one for a perpetual motion
machine.
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OpAmps - Stable Inverting Amplifier
assume VV-GND
I1I2 0
note low input and output impedance, R1R2
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OpAmps - Stable Non-Inverting Amplifier
assume VV-GND
large input impedance Zin 108 W
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OpAmps - Unity Gain Follower
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OpAmps - Current-to-Voltage Converter
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OpAmps - Summing Amplifier
weighted sum? digital to analog converter?
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OpAmps - Bipolar Power Amplifier