[If parameter is not given, you can model parameter to specific character (ex r01, gm1.)]
1. We wish to design the circuit of Fig. 1 for a drain current of 1mA. If W/L = 20/0.18, compute
R1 and R2 such that the input impedance is at least 20kΩ. (𝛍𝛍𝐧𝐧 𝐂𝐂𝐨𝐨𝐨𝐨 = 𝟐𝟐𝟐𝟐𝟐𝟐𝟐𝟐𝟐𝟐/𝐕𝐕 𝟐𝟐 , 𝛌𝛌 = 𝟎𝟎, 𝐕𝐕𝐭𝐭 = 𝟎𝟎. 𝟒𝟒𝟒𝟒)
VDD=1.8 V
500Ω
R1
M1
R2
<Figure 1>
2. Assuming the MOSFET is in saturation, calculate the Rout and Rin of the circuit below. (𝛌𝛌 ≠ 𝟎𝟎)
VDD
RL
Rout
Vb
M1
Rin
RS
<Figure 2>
3. Assuming the MOSFET is in saturation, calculate the small-signal voltage gain of the circuit.
(𝛌𝛌 ≠ 𝟎𝟎)
VDD
RD
RS
Vout
Vin
M1
<Figure 3>
4. The NMOS transistor in the CS amplifier shown in Figure 4 has Vt=0.7V, VA=50V.
(a) Neglecting the Early effect, verify that the MOSFET is operating in saturation with
𝑾𝑾
ID=0.5mA, VOV=VGS-Vt=0.3V. What must the MOSFET’s kn (=𝛍𝛍𝐧𝐧 𝐂𝐂𝐨𝐨𝐨𝐨 ) be? What is the dc
𝑳𝑳
voltage at the drain?
(b) Find Rin and Gain.
(c) If vsig is a sinusoid with a peak amplitude vpeak, find the maximum allowable value of
vpeak for which the transistor remains in saturation. What is the corresponding amplitude
of the output voltage?
(d) What is the value of resistance RS that needs to be inserted in series with capacitor CS
in order to allow us to double the input signal vpeak? What output voltage now results?
5V
300kΩ
5kΩ
Vo
CC2
120kΩ
CC1
Vsig
M3
200kΩ
Rin
<Figure 4>
CS
2kΩ
5kΩ
5. The PMOS transistor in the CS amplifier of Figure 5 has Vt=-0.7V, VA=∞.
(a) Select a value for RS to bias the transistor at ID = 0.3mA and |VOV|=|VGS-Vt|=0.3V. Assume
vsig to have a zero dc component.
(b) Select a value for RD that results in Av=-10 V/V.
(c) If vsig is a sinusoid with a peak amplitude vpeak, find the largest vpeak that the amplifier
can handle while remaining in the saturation region. What is the corresponding signal
at the output?
(d) If to obtain reasonably linear operation, vpeak is limited to 50mV, what value can RD be
increased to while maintaining saturation-region operation? What is the new value of
Av?
2.5V
RS
CS
Rsig
Vsig
M3
RD
-2.5V
<Figure 5>
Vo
CC