Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Solution to Homework #9
1. (a) When the swings are small, we can ignore the current drawn by RL , then IC I1 = VP /RL and
VP
1 since VP
VP + VT
Av1 =
VT .
(b) Assu
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Solution to Homework #8
1. The open-loop gain and I/O impedances are
Av,open = gm1 (R1 + R2 ), Rin,open =
r1 + (R1 |R2 )
, Rout,open = R1 + R2 .
1+
The feedback fac
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Solution to Homework #7
1. First, we determine the open-loop gain and I/O impedances of the feedforward network as follows.
A1 =
(1 + gm1 rO1 )RD
rO1 + RD
, Rin =
,
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Solution to Homework #6
1. (a) The open-loop gain is A1 and the feedback factor is K R1R2 2 . Therefore, the closed-loop gain is
+R
Y
A1
.
=
X
1 + K R1R2 2 A1
+R
(b
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Solution to Homework #4
1. (a) The transistor capacitances are shown in Figure 1(a). CCS1 , C2 , and CL are in parallel. C2 and
CCS2 are grounded on both sides.
(b)
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Solution to Homework #3
1. (a) The DC voltage gain is AV = gm1 . The pole and -3-dB bandwidth of the circuit is
gm2
1
.
gm2 CL
|wp | =
The Bode plot of |Vout /Vin |
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Solution to Homework #2
1. Based on the concept of half-circuit, the output impedance Rout is
Rout = [1 + gm3 (r3 |R1 )]rO3 + r3 |R1 , where R1 = 1 + gm1 r1 |
RS
2
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Solution to Homework #1
1. The voltage at node P is
VP = VCC (I1 + I2 )R1 = VCC 2I0 R1
The peak-to-peak swing of VP is 0 and the common-mode level of VP is VCC 2I0
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Homework #9
Unless otherwise stated, assume VCC = 5 V, VEE = 5 V, VA = , and
1 in the following problems.
1. Consider the emitter follower shown in Figure 1. We ca
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Homework #8
1. Consider the feedback amplier circuit shown in Figure 1. Assume R1 + R2 is not very large, 1
and VA = , determine the closed-loop gain and I/O impeda
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Homework #7
1. Consider the feedback circuit shown in Figure 1, where C1 and C2 are very small and other capacitances
can be ignored. Compute the closed-loop gain a
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Homework #6
1. Calculate the closed-loop gain of the circuits shown in Figure 1. Assume the op amp exhibits an open-loop
gain A1 , but is otherwise ideal. Also = 0.
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Homework #5
1. The circuit shown in Figure 1 is called an active inductor. Neglect other capacitances and assume
= 0, determine Zin . Construct the Bode plot of |Z
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Homework #4
1. For the bipolar circuits shown in Figure 1, identify all of the transistor capacitances and determine which
ones are in parallel and which ones are g
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Homework #3
1. Construct the Bode plot of |Vout /Vin | and determine the -3-dB bandwidth for the circuits shown in Figure
1. Assume VA = but > 0. Neglect other capa
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Homework #2
1. Calculate the voltage gain of the degenerated pair depicted in Figure 1. VA < . (Hint: Av = Gm Rout .)
Figure 1
2. A student has mistakenly used pnp
Department of Electrical Engineering, Tamkang University
Microelectronics (III), Fall 2009
Homework #1
1. In the circuit of Figure 1, I1 = I0 cos wt + I0 and I2 = I0 cos wt + I0 . Plot the waveforms at X, Y , and
P . Determine their peak-to-peak swings an
Department of Electrical Engineering, Tamkang University
Microelectronics, Summer 2008
Solution to Homework #10
1. Based on the concept of half-circuit, the output impedance Rout is
Rout = [1 + gm3 (r3 |R1 )]rO3 + r3 |R1 , where R1 = 1 + gm1 r1 |
RS
2
+ r
Department of Electrical Engineering, Tamkang University
Microelectronics, Summer 2008
Solution to Homework #9
1. The voltage at node P is
VP = VCC (I1 + I2 )R1 = VCC 2I0 R1
The peak-to-peak swing of VP is 0 and the common-mode level of VP is VCC 2I0 R1 .
Department of Electrical Engineering, Tamkang University
Microelectronics, Summer 2008
Solution to Homework #8
1. Let IB be the base current goes through the resistor RP , we have
I1
IREF I1
IB = IB IB =
.
( + 1)
IREF
Next,
IS exp
VB
VB IB RP
I1
= I1 ,
Department of Electrical Engineering, Tamkang University
Microelectronics, Summer 2008
Solution to Homework #7
1. (a) Since Rp is in parallel connection with r1 , we have
Rout = [1 + gm1 (r1 |RP |rO2 )]rO1 + (r1 |RP |rO2 ).
(b) Since Rp is in parallel con
Department of Electrical Engineering, Tamkang University
Microelectronics, Summer 2008
Solution to Homework #5
1. To nd the closed-loop gain, we consider the equivalent circuit shown in Figure 1(a). By KCL, we have
Vin VX
A0 V1 VX
VX
+
=
VX =
Rin
R1
R2
T
Department of Electrical Engineering, Tamkang University
Microelectronics, Summer 2008
Solution to Homework #4
1. The input impedance Rin is given by
Rin =
1
1
1
.
50 =
gm1 =
gm1
gm1
50
The output impedance is Rout = RD = 500 . Since M1 must operate in
Department of Electrical Engineering, Tamkang University
Microelectronics, Summer 2008
Solution to Homework #3
1. Since ID1 is 0.5 mA, assume M1 operates in the saturation region, we have
ID1 =
1
W
1
20
n Cox (VGS VT H )2 0.5 103 = 200 106
(VGS 0.4)2 VG
Department of Electrical Engineering, Tamkang University
Microelectronics, Summer 2008
Solution to Homework #2
1. (a) VGS = 1 V and VDS = VDD ID RD . We assume M1 operates in the saturation region, the drain
current is given by
ID =
W
1
W
1
n Cox (VGS VT
Department of Electrical Engineering, Tamkang University
Microelectronics, Summer 2008
Solution to Homework #1
1. This combination can be treated as a series connection of two resistors. The width and length of Meq are
Leq = 2L and Weq = W .
2. Since the
Department of Electrical Engineering, Tamkang University
Microelectronics, Summer 2008
Homework #10
1. Calculate the voltage gain of the degenerated pair depicted in Figure 1. VA < . (Hint: Av = Gm Rout .)
Figure 1
2. A student has mistakenly used pnp cas