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A MOSFET amplifier can be simplified as the equivalent circuit model shown below (very similar to the BJT version), where gm (transconductance) and RL (load resistor) can be designed to have the desired gain of the amplifier. (a) Determine the voltage gain of this MOS amplifier (Vout /Vin )?(10/10) (b) Design the load resistor RL to achieve a voltage gain ( Vout /Vin ) of 60 dB if gm = 25 mA/V.(10/100) (b) Design the transconductance gm to achieve a voltage gain (Vout /Vin ) of 40 dB if RL = 1.2 Kohm.(10/100)

A MOSFET amplifier can be simplified as the equivalent circuit model shown below (very similar to the BJT version), where gm (transconductance) and RL (load resistor) can be designed to have the desired gain of the amplifier. (a) Determine the voltage gain of this MOS amplifier (Vout /Vin )?(10/10) (b) Design the load resistor RL to achieve a voltage gain ( Vout /Vin ) of 60 dB if gm = 25 mA/V.(10/100) (b) Design the transconductance gm to achieve a voltage gain (Vout /Vin ) of 40 dB if RL = 1.2 Kohm.(10/100)

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A MOSFET amplifier can be simplified as the equivalent circuit model shown below (very similar to the BJT version), where gm (transconductance) and RL (load resistor) can be designed to have the desired gain of the amplifier. (a) Determine the voltage gain of this MOS amplifier (Vout /Vin )?(10/10) (b) Design the load resistor RL to achieve a voltage gain ( Vout /Vin ) of 60 dB if gm = 25 mA/V.(10/100) (b) Design the transconductance gm to achieve a voltage gain (Vout /Vin ) of 40 dB if RL = 1.2 Kohm.(10/100)

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All the capacitors in the circuit shown below have large values, i.e. can be considered short circuits at low frequencies. The threshold voltage of the NMOS transistor in the common source amplifier circuit is 1 V and the kn' (W/L) = 1 mA/V2.a) Find the required DC value of the Vas that would establish a dc bias current of 1) = 2 mA; b) Find the required values for the resistances RG1 and Rg2 so both the value of VGS from part (a) can be assured and the value of the input resistance (Rin) of this amplifier to be equal or higher than 3 M22; c) Determine a value for R, so the open circuit voltage gain of this amplifier A, to be -10. NOTE: Use the small signal model discussed in lecture notes.
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In this question, you are asked to find the effective transconductance (Gm) and the resistance into the drain (Rx) of a common-source amplifier with source degeneration. Based on the results, the voltage gain of a common-source amplifier with source degeneration will be evaluated a) The figures shown below are a circuit to find the effective transconductance (G) of the NMOSEFT with source degeneration (left) and its corresponding small-signal circuit (right). It is noted that the output is shorted to VDD (ac grounded) since the definition of effective transconductance is the ratio between the short-circuit output current and the input signal voltage. Prove that Gm is given by Gm = id/vin = gm/1+gmRs In this calculation, the current passing through ro can be neglected since, in general, ro is very large when the NMOSFET operates in saturation region and so this current is very small. Thus, the indication of id is the current of the voltage-controlled current source (gmvgs) only. b) The figure shown below is the method to evaluate the resistance looking into the drain (i.e. Rx) of a source-degenerated NMOSFET. The circuit is shown on the left while the equivalent small-signal modeling is shown on the right. It is noted that the bias condition (VBiAS) is set so that the values of gm and ro, can be defined. Moreover, there is no input signal (i.e. Vin = 0) since we would like to see the value of Rx which is due to the circuit only but not due to the external effect. Based on the above small-signal model, prove that RX = ro(1 + gmRS) The complete common-source amplifier with source degeneration is shown below. c) The complete common-source amplifier with source degeneration is shown below. Prove that the voltage gain of this amplifier is given by v. Vin Explain the reason(s) why the voltage gain is negative. What is the physical meaning of negative voltage gain?

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