The MOSFET in the common-source amplifier in Fig. 10.6.1

Figure 10.6.1
has $g_{m}=$ $5 \mathrm{~mA} / \mathrm{V}, r_{o}=20 \mathrm{k} \Omega, C_{g s}=5 \mathrm{pF}$, and $C_{g d}=1 \mathrm{pF}$, and the total capacitance at the output node, $C_{L}$, is $10 \mathrm{pF}$.
(a) Find the value of the midband voltage gain.
(b) Use the method of short-circuit time constants to determine the lower 3-dB frequency, $f_{L}$. Which capacitor dominates the determination of $f_{L}$ ?
(c) Use the method of open-circuit time constants to determine the upper 3-dB frequency, $f_{H}$. Which capacitor dominates the determination of $f_{H}$ ?

Question

The MOSFET in the common-source amplifier in Fig. 10.6.1

Figure 10.6.1
 has $g_{m}=$ $5 \mathrm{~mA} / \mathrm{V}, r_{o}=20 \mathrm{k} \Omega, C_{g s}=5 \mathrm{pF}$, and $C_{g d}=1 \mathrm{pF}$, and the total capacitance at the output node, $C_{L}$, is $10 \mathrm{pF}$.
(a) Find the value of the midband voltage gain.
(b) Use the method of short-circuit time constants to determine the lower 3-dB frequency, $f_{L}$. Which capacitor dominates the determination of $f_{L}$ ?
(c) Use the method of open-circuit time constants to determine the upper 3-dB frequency, $f_{H}$. Which capacitor dominates the determination of $f_{H}$ ?

Quizplus · Accepted Answer

The Answer of The MOSFET in the common-source amplifier in Fig. 10.6.1

Figure 10.6.1
 has $g_{m}=$ $5 \mathrm{~mA} / \mathrm{V}, r_{o}=20 \mathrm{k} \Omega, C_{g s}=5 \mathrm{pF}$, and $C_{g d}=1 \mathrm{pF}$, and the total capacitance at the output node, $C_{L}$, is $10 \mathrm{pF}$.
(a) Find the value of the midband voltage gain.
(b) Use the method of short-circuit time constants to determine the lower 3-dB frequency, $f_{L}$. Which capacitor dominates the determination of $f_{L}$ ?
(c) Use the method of open-circuit time constants to determine the upper 3-dB frequency, $f_{H}$. Which capacitor dominates the determination of $f_{H}$ ?

The MOSFET in the Common-Source Amplifier in Fig gm=g_{m}=gm​= 5 mA/V,ro=20kΩ,Cgs=5pF5 \mathrm{~mA} / \mathrm{V}, r_{o}=20 \mathrm{k} \Omega, C_{g s}=5 \mathrm{pF}5 mA/V,ro​=20kΩ,Cgs​=5pF

The MOSFET in the Common-Source Amplifier in Fig $g_{m}=$ $5 \mathrm{~mA} / \mathrm{V}, r_{o}=20 \mathrm{k} \Omega, C_{g s}=5 \mathrm{pF}$