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A source follower (Common Drain Amplifier), shown below, is required to connect a high-resistance source to a load whose resistance RL is 2 kohm (a) What is the maximum output resistance Ro that the source follower must have if the gain Av value = 0.85 V/V ? (b) Find the value of gm. (c) If the MOSFET has kn = 10 mA/V2, at what current In must it be biased? (d) At what overdrive voltage Vov is the MOSFET operating?

A source follower (Common Drain Amplifier), shown below, is required to connect a high-resistance source to a load whose resistance RL is 2 kohm (a) What is the maximum output resistance Ro that the source follower must have if the gain Av value = 0.85 V/V ? (b) Find the value of gm. (c) If the MOSFET has kn = 10 mA/V2, at what current In must it be biased? (d) At what overdrive voltage Vov is the MOSFET operating?

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A source follower (Common Drain Amplifier), shown below, is required to connect a high-resistance source to a load whose resistance RL is 2 kohm (a) What is the maximum output resistance Ro that the source follower must have if the gain Av value = 0.85 V/V ? (b) Find the value of gm. (c) If the MOSFET has kn = 10 mA/V2, at what current In must it be biased? (d) At what overdrive voltage Vov is the MOSFET operating?

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D *7.121 The MOSFET in the circuit of Fig. P7.121 has Vt = 0.8 V, kn = 5 mA/V2, and VA = 40 V. (a) Find the values of RS, RD, and RG so that ID = 0.4 mA, the largest possible value for RD is used while a maximum signal swing at the drain of ±0.8 V is possible, and the input resistance at the gate is 10 MΩ. Neglect the Early effect. (b) Find the values of gm and ro at the bias point. (c) If terminal Z is grounded, terminal X is connected to a signal source having a resistance of 1 MΩ, and terminal Y is connected to a load resistance of 10 kΩ, find the voltage gain from signal source to load. (d) If terminal Y is grounded, find the voltage gain from X to Z with Z open-circuited. What is the output resistance of the source follower? Figure P7.121 (e) If terminal X is grounded and terminal Z is connected to a current source delivering a signal current of 50 μA and having a resistance of 100 kΩ, find the voltage signal that can be measured at Y. For simplicity, neglect the effect of ro.D *7.121 The MOSFET in the circuit of Fig. P7.121 has Vt = 0.8 V, kn = 5 mA/V2, and VA = 40 V. (a) Find the values of RS, RD, and RG so that ID = 0.4 mA, the largest possible value for RD is used while a maximum signal swing at the drain of ±0.8 V is possible, and the input resistance at the gate is 10 MΩ. Neglect the Early effect. (b) Find the values of gm and ro at the bias point. (c) If terminal Z is grounded, terminal X is connected to a signal source having a resistance of 1 MΩ, and terminal Y is connected to a load resistance of 10 kΩ, find the voltage gain from signal source to load. (d) If terminal Y is grounded, find the voltage gain from X to Z with Z open-circuited. What is the output resistance of the source follower? Figure P7.121 (e) If terminal X is grounded and terminal Z is connected to a current source delivering a signal current of 50 μA and having a resistance of 100 kΩ, find the voltage signal that can be measured at Y. For simplicity, neglect the effect of ro.
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Figure P7.33 shows a discrete-circuit amplifier. The input signal vsig is coupled to the gate through a very large capacitor (shown as infinite). The transistor source is connected to ground at signal frequencies via a very large capacitor (shown as infinite). The output voltage signal that develops at the drain is coupled to a load resistance via a very large capacitor (shown as infinite). All capacitors behave as short circuits for signals and as open circuits for dc. (a) If the transistor has Vt = 1 V, and kn = 4 mA/V2 , verify that the bias circuit establishes VGS = 1.5 V, ID = 0.5 mA, and VD = +7.0 V. That is, assume these values, and verify that they are consistent with the values of the circuit components and the device parameters. (b) Find gm and ro if VA = 100 V. (c) Draw a complete small-signal equivalent circuit for the amplifier, assuming all capacitors behave as short circuits at signal frequencies. (d) Find Rin, vgs/vsig, vo/vgs, and vo/vsig.

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