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The following circuit is a common drain amplifier. A small-signal vin is applied to the gate input with a DC bias of V GS. Express the voltage gain A0 using the symbols used in the figure. Here, r0 and gm are the output resistance and the transconductance of the MOSFET, respectively.

The following circuit is a common drain amplifier. A small-signal vin is applied to the gate input with a DC bias of V GS. Express the voltage gain A0 using the symbols used in the figure. Here, r0 and gm are the output resistance and the transconductance of the MOSFET, respectively.

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  1. The following circuit is a common drain amplifier. A small-signal vin is applied to the gate input with a DC bias of V GS. Express the voltage gain A 0 using the symbols used in the figure. Here, r 0 and g m are the output resistance and the transconductance of the MOSFET, respectively.

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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?

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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Figure P5-1 shows a common source single transistor MOSFET amplifier utilizing an N-Channel Enhancement Mode MOSFET. The term "common source" refers to the source terminal being shared by both the input circuit and the output circuit. The parameters for the MOSFET and the supply voltage are also given. Hand Analysis P1. In terms of DC bias, determine a value for VGS to set the drain current ID to 5 mA. Also determine a value for RD to set the VDS bias to 6 V. P2. In terms of small-signal parameters, determine the transconductance gm of this amplifier as well as the voltage gain, Av. P3. If vgs is a 0.1 Vpk sinewave at a frequency of 1 kHz [ie. vgs = 0.1sin(2pift)V ] determine an expression for the output voltage vOUT as a function of time. Sketch vIN and vOUT for two complete cycles, including the DC bias for each signal. Simulation P4. Simulate the circuit of Figure P5-1 to verify your hand analysis and create a plot similar to P3 as part of your prelab. Use the virtual MOSFET model in simulation with SPICE parameters VT0 = 1.8 V and KP = 120 mA/V2. (The default values of 100um for W and L will be fine since their ratio equals unity.)
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Consider the following amplifier circuit. Both MOSFET’s have the following specifications: (W/L) = (6µm/0.18µm), processing parameters kp = µpCox = 70µA/V2 , kn = µnCox = 270µA/V2 , |Vt| = 0.45 V, V Ω A = 12.5 V/µm = VA, and Q1 is biased so that Vov = 200mV, gate of Q2 is at DC voltage VG = 0.96 V and VDD = 1.8 V. a. What is the configuration of amplifier, i.e. CE or CB or CD or CS or CG or CC or CD or CS with active load or CG with active load or CE with active load or CB with active load or CD with active load or CC with active load or CE using 0.18µm technology? Or none of the above the correct answer is b. Find the small-signal output resistance Rout and input resistance Rin looking into gate Q1 c. Calculate small-signal voltage gain of the amplifier Av = [vo/vi ] d. What is the voltage swing at the output, i.e. vomax and vomin ? e. Calculate the power consumed by the amplifier.
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