1 the 741 operational-amplifier. reference bias current : the 741 op-amp circuit. reference bias...
TRANSCRIPT
![Page 1: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/1.jpg)
1
The 741 Operational-Amplifier
![Page 2: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/2.jpg)
Reference Bias Current : The 741 op-amp circuit.
Reference Bias Current
![Page 3: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/3.jpg)
DC Analysis of the 741Reference Bias Current
VCC
-VEE
![Page 4: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/4.jpg)
Bias for input stage The 741 op-amp circuit.
Bias for input stage
IC10
![Page 5: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/5.jpg)
Input Stage Bias
IC10 can be determined by knowing IREF and R4
+
-
+
-
VBE11 VBE10
+
-
+
IC10
1010
10
111011
11111111
10
10101010
lnlnln
ln
ln
11
10
C
REFT
S
CT
S
REFTBEBE
S
REFTBE
VV
SC
S
CTBE
VV
SC
I
IV
I
IV
I
IVVV
I
IVVeII
I
IVVeII
T
BE
T
BE
![Page 6: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/6.jpg)
Biasing Input Stage : The 741 op-amp circuit.
IC3 IC4
IC1 IC2
![Page 7: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/7.jpg)
The dc analysis of the 741 input stage.
npn β very high
Base current IE/1+βP
Relationship IREF & IO
Base currents add together
IIAs CP 2 1 10
![Page 8: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/8.jpg)
8
A Simple BJT Current Source
![Page 9: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/9.jpg)
Negative Feed-back Loop : 741 input stage.
Negative Feed back Loop
For some reason I in Q1 & Q2 increasesCauses current pulled from Q8 to increase
Output current of Q8 Q9 correspondingly increase
Since Ic10 remains constant, it forcescombined current of Q3 & Q4 to decrease
![Page 10: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/10.jpg)
Input Stage : The 741 op-amp circuit.
IC7
![Page 11: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/11.jpg)
The dc analysis of the 741 input stage, continued.
Ic5=I
Bias Current of Q7
25
1
3
6
7 4
![Page 12: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/12.jpg)
The dc analysis of the 741 input stage, continued.
50 KΩ
![Page 13: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/13.jpg)
The 741 op-amp circuit : SECOND STAGE
IC16 IC17
![Page 14: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/14.jpg)
DC Analysis : Second Stage
Neglect Base Current of Q23
IC17=IC13B
Q13 is lateral pnp transistorQ13B has a scale of 0.75 times that of Q12
IC13B=0.75 IREFIREF = 0.73 mA & βP>>1IC13B = 550 µA & IC17 = 550 µA
![Page 15: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/15.jpg)
Output Stage Bias : The 741 op-amp circuit.
![Page 16: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/16.jpg)
The 741 output stage without the short-circuit protection devices.
Q13 is lateral pnp transistorIS of Q13A is 0.25 times IS of Q12
Neglect Base current of Q14 & Q20
Base Current of Q23 is 180/50=36 μ ANegligible as assumed
![Page 17: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/17.jpg)
Output Stage Bias
Voltage VBE18 ≈ 0.6V Current Thru R10=0.6/40k=15 µ A
VBB
+
-
14 20
![Page 18: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/18.jpg)
Summary Collector Currents : 741 Op Amp
![Page 19: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/19.jpg)
Small-signal analysis of the 741 input stage.
Collectors Q1 & Q2 connected to dc voltage so are groundedQ3 & Q3 are biased by constant current source so are open cct
![Page 20: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/20.jpg)
Small-signal analysis of the 741 input stage.
Input appears across four input resistors
ee
i
b
iid r
i
v
i
vR )1(4)1(
![Page 21: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/21.jpg)
The 741 op-amp circuit.
![Page 22: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/22.jpg)
Small signal model :
The load circuit of the input stage.
![Page 23: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/23.jpg)
The load circuit of the input stage
Q5 & Q6 are identical and their bases are tied togetherSo their collector currents are equal
![Page 24: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/24.jpg)
The load circuit of the input stage
![Page 25: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/25.jpg)
Output Resistance : 741 Op AmpRo1 is parallel equivalent of Ro4 & Ro6
Output Resistance Ro1
Assume that common bases of Q3 & Q4
are at virtual ground
MRI
VrrR
equationrRgrR
CircuitBaseCommon
o
AoeE
Emoo
5.10
,,
118.6 ...... ||1
4
4
![Page 26: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/26.jpg)
Output Resistance : 741 Op Amp
Output Resistance Ro1
MRI
VrRR
equationrRgrR
CircuitBaseCommon
o
AoE
Emoo
2.18
,,
118.6 ...... ||1
6
2
6
Assume that the base of Q6 is at virtual groundBecause signal is very small
![Page 27: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/27.jpg)
Output Resistance : 741 Op Amp
Ro1 is parallel equivalent of Ro4 & Ro6
Ro1=Ro4||Ro6
Ro1=6.7 MΩ
Output Resistance Ro1
![Page 28: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/28.jpg)
Figure 9.22 Small-signal equivalent circuit for the input stage of the 741 op amp.
![Page 29: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/29.jpg)
Second Stage :The 741 op-amp circuit.
![Page 30: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/30.jpg)
Figure 9.24 The 741 second stage prepared for small-signal analysis.
![Page 31: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/31.jpg)
Input Resistance : Second Stage
![Page 32: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/32.jpg)
Transconductance : Second Stage
Thus current through the output resistance of Q13B is zero
![Page 33: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/33.jpg)
Output Resistance R02 : Second Stage
R02
![Page 34: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/34.jpg)
Output Resistance R02 : Second Stage
R02
Since the resistance between the base of Q17 and ground is relatively small, The base is grounded and circuit is CB
![Page 35: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/35.jpg)
Output Resistance R02 : Second Stage
R02
![Page 36: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/36.jpg)
Output Resistance R017
Since the resistance between the base of Q17 and ground is relatively small, The base is grounded and circuit is CB
![Page 37: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/37.jpg)
Figure 9.25 Small-signal equivalent circuit model of the second stage.
![Page 38: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/38.jpg)
Figure 9.27 Thévenin form of the small-signal model of the second stage.
Open Circuit Voltage Gain =
![Page 39: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/39.jpg)
Output Stage :The 741 op-amp circuit.
![Page 40: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/40.jpg)
The 741 output stage.
![Page 41: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/41.jpg)
The 741 output stage.
• Input from second stage Q17
• Loaded with 2 kΩ resistor
• Q18 & Q19 and R10 provide Class AB bias to output stage.
• Q14 & Q20 are output transistors
• Output stage is driven by emitter follower Q23 acts as buffer
![Page 42: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/42.jpg)
Output Voltage LimitsMaximum positive output voltage vomax is limited by input circuitSaturation of Q13A
Minimum negative output voltage vomin is limited by input circuit Saturation of Q17
1413max BEAECCCo VVVv
![Page 43: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/43.jpg)
Small Signal Model for the 741 output stage.
vo2=-Gm2R02vi2
Gm2 = 6.5mA/V & RO2 = 81kΩ
Rin3 is input resistance of the output stage with load RL
![Page 44: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/44.jpg)
Input resistance Rin3 of output stage
Rin
Rin3
inineb
bin RRr
i
vR 232323
23
233 1
![Page 45: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/45.jpg)
Input resistance Rin
Rin20
Rin
Rout18
Rin=Rin20||Rout18
Suppose Q20 is conducting and Q14 is cut-off
![Page 46: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/46.jpg)
Input resistance Rin20
LLeb
bin RRr
i
vR 202020
20
2020 1 Rin20
![Page 47: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/47.jpg)
Input resistance Rout18
Rout18
Aout rR 01318
Rout18 is ro13A in series with output resistance of Q18 & Q19
ro13A >>Output resistance of Q18 & Q19
Output resistance of Q18 & Q19
= 163 Ω
![Page 48: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/48.jpg)
Input resistance Rin3 of the output stage
Rin20
Rin
Rout18
Rin=Rin20||Rout18
Rin3
inin RR 233
Aout rR 01318
Lin RR 2020
β20 = β23 = 50 , RL= 2kΩ, ro13A= 280kΩRin3 = 3.7 MΩ
![Page 49: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/49.jpg)
Small Signal Model for the 741 output stage.
Rin3 = 3.7 MΩ Ro2 = 81 kΩ
Rin3 >> Ro2
So Rin3 will have little effect On the performance of the op
amp = -515 V/V
![Page 50: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/50.jpg)
Open Circuit Overall Voltage Gain Gvo
Small Signal Model for the 741 output stage.
LR
o
ovo v
vG
23
![Page 51: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/51.jpg)
Open Circuit Overall Voltage Gain Gvo
LR
o
ovo v
vG
23
Q14 , Q20 & Q23 are common collector circuits, So gain is unity
13 voG
![Page 52: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/52.jpg)
Circuit for finding the output resistance Rout.
Exact Value of Rout will depend upon which transistor (Q14 or Q20) is conductingSuppose Q20 Is conducting and Q14 is cut-off.
Input source feeding the output stage is grounded
![Page 53: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/53.jpg)
Circuit for finding the output resistance Rout.
2
1
23
23
e
eout i
vR
![Page 54: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/54.jpg)
Output Short Circuit Protection Stage :The 741 op-amp circuit.
![Page 55: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/55.jpg)
Output Short-Circuit Protection
• If any terminal of the IC is short circuited to one of the power supplies, IC will burnout.
• Protection Circuit limits the current in the output transistors in the event of short circuit.
![Page 56: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/56.jpg)
Output Short-Circuit ProtectionAgainst maximum current the op amp can source
• In normal case– Current thru the emitter of
Q14 is 20mA, voltage drop across R6 is approx 540mV and Q15 is off
• In the event of short circuit,– if current in the emitter of
Q14 exceeds 20mA, voltage drop across R6 will increase above 540mV and Q15 will conduct.
• Robs some of the current supplied by Q13A, thus reducing the base current of Q14.
• This limits the current that the op amp supplies from the output terminal in the outward direction to 20mA.
![Page 57: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/57.jpg)
Output Short-Circuit ProtectionAgainst maximum current the op amp can source
• In normal case– Current thru the emitter of
Q20 is 20mA, voltage drop across R7 is approx 540mV and Q21 is off
• In the event of short circuit,– if current in the emitter of
Q20 exceeds 20mA, voltage drop across R7 will increase above 540mV and Q21 will conduct.
• Robs some of the current supplied by Q24, thus reducing the base current of Q20.
• This limits the current that the op amp supplies from the output terminal in the inward direction to 20mA.
![Page 58: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/58.jpg)
Small Signal Gain
Gain is found from the cascade of the equivalent circuits of the op amp
![Page 59: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/59.jpg)
Frequency Response
![Page 60: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/60.jpg)
Cc
Frequency Response
![Page 61: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/61.jpg)
Frequency Response
Cc introduces a dominant low-frequency pole
Using Miller’s theorem, the effective capacitance due to Cc between the base of Q16 and ground is
The total resistance between base of Q16 and ground is
Cc
![Page 62: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/62.jpg)
Figure 9.32 Bode plot for the 741 gain, neglecting nondominant poles.
The convenience of use of internally compensated 741 is achieved at the expense of a great reduction in open loop gain--- externally compensated op amp.
![Page 63: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/63.jpg)
Slew Rate
![Page 64: 1 The 741 Operational-Amplifier. Reference Bias Current : The 741 op-amp circuit. Reference Bias Current](https://reader036.vdocuments.mx/reader036/viewer/2022062407/56649db65503460f94aa7b49/html5/thumbnails/64.jpg)
Slew rate
em rG
21
I
Vr Te
TTC
t V
SR
VC
I
42
tTVSR
4