ece3110 homework #9 fall 2011ece3110/ece3110f11_hw9sol.pdf · 2011. 12. 5. · ece3110 homework #9...
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![Page 1: ECE3110 Homework #9 Fall 2011ece3110/ECE3110F11_HW9sol.pdf · 2011. 12. 5. · ECE3110 Homework #9 Fall 2011 2 2. For Vsig=Vin=1+6sin( ωt)V and VDD=VSS=5V. Assume V1 (1a) is biased](https://reader033.vdocuments.pub/reader033/viewer/2022051410/6038640fae80026fff03c123/html5/thumbnails/1.jpg)
ECE3110 Homework #9 Fall 2011
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1. Label the circuits below as Class A, Class B, or Class AB.
![Page 2: ECE3110 Homework #9 Fall 2011ece3110/ECE3110F11_HW9sol.pdf · 2011. 12. 5. · ECE3110 Homework #9 Fall 2011 2 2. For Vsig=Vin=1+6sin( ωt)V and VDD=VSS=5V. Assume V1 (1a) is biased](https://reader033.vdocuments.pub/reader033/viewer/2022051410/6038640fae80026fff03c123/html5/thumbnails/2.jpg)
ECE3110 Homework #9 Fall 2011
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2. For Vsig=Vin=1+6sin(ωt)V and VDD=VSS=5V. Assume V1 (1a) is biased for correct operation. Assume
(1b) is biased at = 1. Sketch the output waveforms for all the circuits in Problem 1.
3. Calculate the efficiency for circuit 1b. Use = 1 and =10kΩ, VDD=VSS=5V.
=
= 14
= 14 4.8
110 4.85 = 11.5%
This is assuming a symmetric output and symmetric power supplies of equal value.
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ECE3110 Homework #9 Fall 2011
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The output is not symmetric in this case. One way of getting the average is to take the rms value.
= ∗ = !"
∗
=#$ − #&'
√2 *
!"=
4.8 − 0.2√2
*
10 = 1.06,
Only one power supply of +5V:
- = ∗ = 1 ∗ 5 = 5
= -
= 1.065 = 21.2%
4. The datasheet of a bipolar transistor contains the following information:
Maximum allowable junction temperature TJmax = 100°C
Maximum power dissipation PDmax = 2 W at case temperature TC = 45°C
Junction-to-case thermal resistance θJC = 60 °C/W
Junction-to-ambient thermal resistance θJA = 100 °C/W
(a) What is the maximum case temperature to ensure safe operation at 0.2W?
(b) What is the case temperature when the transistor dissipates 500mW and the room is at 25oC.
![Page 4: ECE3110 Homework #9 Fall 2011ece3110/ECE3110F11_HW9sol.pdf · 2011. 12. 5. · ECE3110 Homework #9 Fall 2011 2 2. For Vsig=Vin=1+6sin( ωt)V and VDD=VSS=5V. Assume V1 (1a) is biased](https://reader033.vdocuments.pub/reader033/viewer/2022051410/6038640fae80026fff03c123/html5/thumbnails/4.jpg)
ECE3110 Homework
For Problems 5-8. The above design uses
µpCox=60µA/V2, |VA|=40V. Neglect the effect of V
5. Fill in the empty spaces in the table above if A1=10V/V and the overall gain is A=200V/V.
6. (a) If C2=0.2pF, find the frequency of the second pole,
(b) Find the value of CC that results in
(c) Find the phase margin. Is the system stable
./*
.0 = 1 2#*3
PM=90 − tan89 :;:<=
− tan89 1:;:>
? where
PM=90 − tan89 1 @AAB9C9*B? − tan89 1@AA
C9D
Q (W/L) µCox (µA/V2) I(mA)
Q1 20 60 480E
Q2 20 60 480E
Q3 11 180 480E
Q4 11 180 480E
Q5 40 60 960E
Q6 10 180 960E
Q7 40 60 960E
Q8 40 60 960E
Homework #9 Fall 2011
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The above design uses ±5V power supplies. Let |Vt|=0.5V, µnCox=180
|=40V. Neglect the effect of VA on the bias currents. Use the following table:
Fill in the empty spaces in the table above if A1=10V/V and the overall gain is A=200V/V.
ind the frequency of the second pole, fp2.
that results in ft =300MHz.
Find the phase margin. Is the system stable?
* = F*2GH*
= 1.92G0.2I = 1,512KLM
1 #N3O
? H = 12#N*3:;
? = 9#*3@AAB = .53IQ
? where .R = 1 2B=*3O
? = 1 9.S#*3A.C@/? = 571KLM
1@AABC9DB? = 90 − 11 − 30 = 49 (STABLE!)
Vov(V) VGS(V) gm(mA/V) ro(kΩ)
0.9 1.4 1 83.3
0.9 1.4 1 83.3
0.7 1.5 1.4 83.3
0.7 1.5 1.4 83.3
0.9 1.4 2.2 41.7
1.03 1.5 1.9 41.7
0.9 1.4 2.2 41.7
0.9 1.4 2.2 41.7
=180µA/V2,
on the bias currents. Use the following table:
Fill in the empty spaces in the table above if A1=10V/V and the overall gain is A=200V/V.
IQ
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ECE3110 Homework
The above design uses ±1.5V power supplies. Let
µpCox=60µA/V2, |VA|=15V. Neglect the effect of V
7. (a) Find the input common mode range and the range allowed for
(b) Fill in the empty spaces in the table above.
Homework #9 Fall 2011
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1.5V power supplies. Let IREF=300µA, |Vt|=0.7V, µnCox=180
|=15V. Neglect the effect of VA on the bias currents. Use the following table:
Find the input common mode range and the range allowed for vo.
Fill in the empty spaces in the table above.
=180µA/V2,
on the bias currents. Use the following table:
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ECE3110 Homework #9 Fall 2011
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8. Find the overall gain of the op amp. Find A1, A2, and the dc open loop voltage gain.
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ECE3110 Homework #9 Fall 2011
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9. What is the overall voltage gain if a load resistor is placed on the output, RL=2k.
10. (a) If C2=1pF, find the frequency of the second pole, fp2.
(b) Find the value of CC that results in ft =200MHz.
(c) Find the phase margin. Is this system stable? If not, how can it be made stable?