The amplifier circuit below uses an n channel FET with gm = 4.74 mS and ID0 = 4.53 mA. The resistor R1 = 2.38 kΩ and VDD = 20.7 V. a. Analyse the circuit to find an equation for the output voltage in terms of the input voltage. You do not need to submit this equation for this quiz, but you will need it to solve the following problems. (Hint: begin by using KVL to find an equation for vout in terms of iD and values we already know. Then write an equation for the FET that gives iD in terms of vGS. Combine these two equations to eliminate iD. ) ) In the following parts, give your answer to 3 siginficant figures as usual (except for part c), but keep intermediate results to more significant figures, otherwise rounding errors may lead to incorrect answers. b. What is the small signal gain of the amplifier (dvout dvin ) ? −11.3 c. What is the minimum output voltage of the circuit? (For this part only, give your answer to the nearest whole number. ) 0 V d. What is the (minimum) value of vin that corrsponds to the output voltage from part c)? Number V e. What is the maximum output voltage of the circuit? 20.7 V f. What is the (maximum) value of vin that corrsponds to the output voltage from part e)? Number Units
Consider the MOSFET amplifier circuits below. For each circuit, Identify the amplifier type. Draw the small-signal circuit of the amplifier using the pi-model for the MOSFET, Draw the small-signal circuit of the amplifier using the T-model for the MOSFET. Derive an expression for vo/vi. Derive an expression for vo/vsig . Derive expressions for Ri and Ro.
A circuit requires the use of a transistor with a transconductance of 0.5 S. A bipolar transistor with β = 60 and a MOSFET with Kn = 25 mA/V2 are available. Which transistor would be preferred and why?
B) For the circuit in the following Figure. (20 points) a. Determine the following DC values for the amplifier: VB, VE, IE, IC, VC, VCE, re′ b. Determine the following values for the amplifier: Rin(base) , Rin(tot) , Rout , Av. c. Assume that a 600 Ω, 12 μV rms voltage source is driving the amplifier. Determine Av′ and the overall voltage gain by considering the attenuation in the base circuit and RL. d. Find the total output voltage. e. Draw the AC load line.
P 2. In the circuit below, amplifiers A and B must be connected in cascade between a source S with Vs 10 mV and Rs = 100 kΩ, and a 100 Ω load. Your task is to decide how the amplifiers should be connected. The amplifiers have gain G, input resistance Rx, and output resistance Ry as follows: For amplifier A: G = 100 V/V, Rx = 10 kΩ, Ry = 10 kΩ For amplifier B: G = 1 V/V, Rx = 100 kΩ, and Ry = 100 Ω a) Find the voltage gain V0(s)/Vs(s) as a ratio and in dB for the case SABL where A precedes B b) Find the voltage gain V0(s)/Vs(s) as a ratio and in dB for the case SBAL where B precedes A c) Which amplifier arrangement is best?
9.65 A bipolar differential amplifier with I = 0.2 mA utilizes transistors for which VA = 20 V and β = 100. The collector resistances RC = 10 kΩ and are matched to within 10%. Find: (a) the differential gain (b) the common-mode gain and the CMRR if the bias current I is generated using a simple current mirror (c) the common-mode gain and the CMRR if the bias current I is generated using a Wilson mirror. (Refer to Eq. 8.98 for Ro of the Wilson mirror. ) Ro ≃ 12 β ro3
Be certain to include appropriate units. 1 Consider the attached MOSFET C-V characteristic. a. Is this an NFET or a PFET? b. What is the flatband voltage for this device? c. Assuming an N+ doped gate, what is the channel doping concentration? d If this device gate was switched to P+ and nothing else was changed, what would the flatband voltage be? e. If the gate dielectric was doubled in thickness and nothing else was changed, what would the largest capacitance be? Consider the attached MOSFET I-V characteristic. This is not the same device, and is not to scale. f. Is this an NFET or a PFET? g. What is the channel length of the device? h. What would the current ID be at VDS = 10 V for a VGS = 10 V ? NOTE: Graphs are not drawn to scale.
b) There are five different sizes of CMOS inverter gates with one NMOS and one PMOS, including (A) (WL)n = 10, (WL)p = 10, (B) (WL)n = 5, (WL)p = 10, (C) (WL)n = 10, (WL)p = 5, (D) (WL)n = 10, (WL)p = 2, and (E) (WL)n = 2, (WL)p = 10. Please show the relative relationship between (A)-(E), and (1)-(5) in the Voltage Transfer Characteristics Curve Below. (10 points)
Problem 2.1: The N-channel enhancement type MOSFET in the following circuit has kn′ = 200 μA/V2, W/L = 20 /0.18, Vt = 0.6 V and λ = 0.1 V−1. Find the mode of its operation and the drain current in the following cases: (i) VG = 1 V and VD = 0.2 V and (ii) VG = 1 V and VD = 2 V. Key formulae: Cut-off condition VGS < Vt; current ID = 0 Linear region conditions VGS > Vt and VGD > Vt; current ID = kn′WL[(VGS − Vt)VDS − 12 VDS2] Saturation conditions VGS > Vt and VGD < Vt; current ID = 12 kn′WL(VGS − Vt)2(1 + λVDS) Solution: Case (i) VGS = and VGD = hence the mode of operation is ID = Problem 2.2: What is the mode of operation of the transistor in each of the following circuits? Take Vt = −0.8 V Note: Identify the type of the MOSFET transistor and take into account the change of the sign for all the voltages when you check the conditions for cut-off, linear mode and saturation. Solution:
Consider two transistors connected as shown in the circuit below. They have same VGS and VDS. The nominal threshold voltage Vt = 0.5 V a. What mode of operation the transistors are in? b. The two transistors are matched and have the same Vt. However, their W/L ratios has a maximum possible mismatch of 2%, i. e. because of variation in fabrication. What is the maximum resulting mismatch in their drain currents? c. Consider a situation where fabrication mismatch causes a maximum possible mismatch in their threshold voltages of 20 mV and no other mismatch. What is the maximum resulting mismatch in their drain currents?
Question 1 For a PMOS transistor, if the threshold voltage is −0.4 V and the gate-source voltage is −0.2 V, has a channel formed? A. Yes B. No QUESTION 2 For a PMOS transistor, if V th = −0.4 V, VG = 1.2 V and VS = 1.8 V, has a channel formed? A. Yes B. No QUESTION 3 For a PMOS transistor, if Vth = −0.4 V, VG = 1.2 V, VD = 0.9 V, and VS = 1.8 V, what is the operating region? A. cutoff B. saturation C. cannot be determined D. triode QUESTION 4 For a PMOS transistor, if Vth = −0.4 V, VG = 0.9 V, VD = 1.6 V, and VS = 1.8 V, what is the operating region? A. saturation B. cannot be determined C. cutoff D. triode
FETs can be used to either pull an output high or to pull it low, but NFETs are generally better in digital applications for pulling outputs low and PFETs for pulling outputs high. Consider an NFET with characteristics: NMOS: kn′ = 115 μA/V2, VT0 = 0.43 V, λ = 0.06 V−1, VDSAT = 0.6 V, W/L = 2, and a supply voltage of Vdd = 2.0 V. Say the NFET is used to pull a capacitor high: (a) How low can the NFET pull the output voltage and still be turned "on"? (b) Considering your answer to part (a) above, what is the highest output voltage, Vout , max that will be seen using an NFET as a pull-up? (c) When the output voltage is within 0.1 V of its maximum, Vout = Vout,max − 0.1, what state is the NFET in (saturation, cut-off, linear)? (d) What is the current, approximately, through the NFET when Vout = Vout,max − 0.1 ?
(15 points) Match terms with the best description Diode Frequency Spectrum Threshold Voltage MOSFET Saturation Region Triode Diode Capacitance Pn junctions NMOS Decrease Increase Signal Amplifier Resistance Matching PMOS PMOS Amplifier Saturation A. Must be in cutoff or reverse biased for a MOSFET to operate properly B. C. One of the MOSFET operating regions used for switching applications D. Mechanical equivalent is a flapper flow valve. E. VDS > VOV F. Acts as a voltage controlled current source G. Using a full wave rectifier instead of a half wave rectifier will the size of the capacitor H. Characteristic that must be accounted for in high speed applications I. Increases the magnitude of a signal J. If exceeded, an inversion layer forms between the drain and source K. An increase in temperature would cause the current through a diode to L. M. Ensures proper voltages are delivered to the load N. Amplitude and phase components of a signal versus frequency O. Caused by voltage supply limitations and results in the loss of signal information (clipping)
Determine the operating region and drain current for the following transistors. If the transistor is in saturation or triode, determine the drain voltage which is the boundary between those two regions. If the transistor is in cutoff, determine the gate voltage which is the edge of cutoff. The channel length is the minimum value. The NMOS width is 0.90 μm and the PMOS width is 1.8 μm. The channel length is 0.18 μm in all cases. Numerical answers to check your work: (a) drain voltage boundary = 1.00 V, ID = 204 μA (f) drain voltage boundary = 0.800 V, ID = 384 μA
Part A - Determine the operating region Several transistors are shown below with two given voltages between terminals. Identify the operating region for each transistor. All the transistors have K = 0.2 mA/V2, the NMOS transistors have Vto = +1 V, and the PMOS transistors have Vto = −1 V. Drag-and-drop the the appropriate items to their respective bins. Cutoff Triode Saturation Hints Reset Help
Determine the size of each PMOS and NMOS transistor for the NAND gate shown such that it matches the same delay as the inverter in the worst case. In the answers, first number shows the PMOS sizes and the second number shows the NMOS sizes of the NAND gate. (8/1; 4 /1) (2/1; 8/1) (8/1; 0.25/1) (2/1; 1/1) (2/1; 4/1)
Consider a p-channel enhancement mode MOSFET biased as shown in the following figure. Sketch the current-voltage characteristics ( ID vs. VD ) for: (a) VGD = 0; (b) VGD = VT/2; (c) VGD = 2VT.
If we use FET in the amplifier, we want it to work in the region. A. Active B. Saturation C. Triode D. Diode 2. If we use BJT in the amplifier, we want it to work in the region. A. Active B. Saturation C. Triode D. Diode 3. FET have three terminals. They are and 4. BJT have three terminals. They are and 5. In the picture, the transistor is called A. NMOS B. PMOS C. CMOS D. DMOS
The iD−vGS characteristics of the MOSFET transistor in saturation are plotted below for the enhancement-mode and depletion-mode NMOS and PMOS devices. For each curve, write down the conduction type (either NMOS or PMOS) and the mode (enhancement or depletion) of the device. (1)type: mode: (2) type: mode: (3) type: mode: (4) type: mode:
Q3. An n-channel MOSFET (nMOSFET) is connected as shown in the circuit in Fig. Q3. A drain current (ID) equal to 3.2 mA is measured with the supply voltage VSS = 0 V. When VSS is changed to −1 V, the threshold voltage of the nMOSFET changes by 0.258 V (as compared to the threshold voltage when VSS = 0 V ) and the drain current is reduced to 2.8 mA. [Hint: The MOSFET drain current equations are applicable even if V/ ss is not 0 V. Fig. Q3 (a) When VSS = −1 V, does the nMOSFET experience body effect? Why? (2 marks) (b) Which region is the nMOSFET operating in? Why? (3 marks) (c) Calculate the threshold voltage VTH when VSS = −1 V. Neglect channel length modulation. (6 marks)
(A) Assume the threshold voltages for NMOS and PMOS are Vthn and (−Vthp). Give the expressions of the output voltage for each circuit. (5') (1) (2) (3) (4)
(15 points) MOSFETs operation (The values may be changed in the real exam) One curve of an n-channel MOSFET is characterized by the following parameters: ID(Sat) = 2×10−4 A, VDS(sat) = 4 V, and VT = 0.8 V. (a) What is the gate voltage? (b) If VGS = 2 V and VDS = 2 V, determine ID. (c) If VGS = 3 V and VDS = 1 V, determine ID. For saturation region, ID = WμnCox2L(VGS − VT)2
MOSFET device capacitances: Calculate the −3 dB bandwidth of the circuit shown below. Parameters: W1 = 10 μm, L1 = 1 μm, W2 = 2 μm, L2 = 10 μm, VIN = 0.9 V, VDD = 1.8 V. Assume μnCox = 150 μA/V2 and Vtt = 0.5 V. For each MOSFET, consider only the intrinsic gate capacitance (use the parameters on slide 43 of Chapter 2 of the course notes for calculations). Hints: First determine the region of operation of each transistor, i. e. saturation, triode, or cutoff. Use appropriate small-signal models for each transistor: we covered saturation in class, models for other regions can be found by reading sections 1.2 . 8 and 1.3 . 3 in the Carusone textbook.
Problem 4: MOSFET inverse modeling 24 pts Consider the following device:What is Vtn ? What is the region of operation of C ? What is the region of operation of D ? What is ro at point A ? What would ID be at VDS = 10 V and VGS = 5 V ? (neglect channel length modulation)What would ID be at VDS = 15 V and VGS = 4 V ? (do not neglect channel length modulation for this one)
Question 2 (15 points) One I−V curve of an ideal long-channel MOSFET is shown below. You may or may not need the following information: m = 1, L = 2 μm, W = 10 μm, Tox = 10 nm. a) [4 pts] Find the threshold voltage Vt from the plot. b) [5 pts] Calculate the effective carrier mobility μeff. . c) [6 pts] Suppose the gate voltage is changed such that Vgs = 3 V. Calculate IDsat and VDsat , and sketch the I−V curve for the new condition.
Explain what is an inversion layer in your own words. )) Re-draw the given MOSFET diagram above to show how the inversion layer looks like during operation at [i] triode, [ii] pinch-off point and [iii] saturation regions. Explain, in each region, how does that affect current flow from VD to Vs. Also write down the inequalities that are true for each region.
(20 points) Device Level For the Figure 1 is cross section view of an MOS device. (a) What type is this device (NMOS or PMOS)? (b) Considering the potential of each terminal in this figure, determine Source, Drain, Gate, and Substrate terminals and label them on the diagram. (c) Assuming that |Vt| = 0.5 V. Find the region of operation of the device. Ignore body effect. (d) Determine drain current if |K′| = 100 μA/V2, (W/L) = 10, and |λ| = 0.1 V−1. (f) Draw depletion region and the channel on the diagram.
Figure 2 Figure 2 shows an N-MOSFET differential amplifier with passive load. The transistors parameters are VTN = 0.9 V, Kn = 2 mA/V2 and λn = 0. The overall circuit is powered by V+ = 10 V and V− = −10 V, with RD = 16 kΩ and IQ = 1 mA. a) Find the voltages VGS1 and Vo2. b) Calculate the differential gain Ad at vo2. c) If the required gain Ad is 20 V/V, what is the required load RD? Comment on your answer. d) Redesign the diff amp such that VDS2 = VDS2(sat). e) If λn = 0.02 V−1, recalculate Ad using RD found in d ). What is Acm and CMRRdB?
(CLO 1) Given the circuit below with NMOS transistor parameters: kn = 2 mA/V2, Vt = 2 V and VDD = 10 V. (a) (5%) Answer in what mode of operation is this transistor working and explain why. (b) (15%) If ID = 0.5 mA, find: VOV, VO, and RS. (c) (10%) Find the RS value needed to get VO = 5 V. (d) (5%) What biasing or RS resistance value do you need to use in order to reach cutoff mode of operation?
A MOSFET has two modes of operations. For the enhancement mode NMOS and PMOS, VGS is required to turn on the device whereas VGS is not needed to turn on the device for the depletion mode NMOS and PMOS. Please specify what is a mode of a MOSFET shown below (a)-(d), i. e. enhancement mode NMOS, enhancement mode PMOS, depletion mode NMOS, and depletion mode PMOS.
For the current source shown below, assume that transistors M1 and M2 are matched. For both PMOS transistors VTP = −1 V and Kp1 = Kp2 = 0.3 mA/V2 Also take λp = 0( take lambda = 0). Find the output current IQ Choose the answer closest to what you have found! V− = −12 V 0.887 mA 0.787 mA 0.587 mA 1.2 mA 2.4 mA
Given the following circuit label determine the operating state and drain current for the following conditions. Assume VT = 2 V and k = 1 mA/V2
The PMOS transistor shown below has VDD = 2 V, VG = 2 V, RG = 1 kΩ, Kp = 0.1 mA/V2 and Vtp = −1.0 V. Calculate the drain current (ID). Write down the answer only (You don't need to show me your calculation).
The figure below shows NMOS and PMOS devices with drains, source, and gate ports annotated. Determine the mode of operation (saturation, linear, or cutoff) and drain current ID for each of the biasing configurations given below. Use the following transistor data. NMOS: k′n = 115 μA/V2, VT0 = 0.43 V PMOS: k′p = 30 μA/V2, VT0 = −0.4 V. Assume (W/L) = 1 for both NMOS and PMOS a. NMOS: VGS = 2.5 V, VDS = 2.5 V. b. PMOS: VGS = −0.5 V, VDS = −1.25 V. c. NMOS: VGS = 3.3 V, VDS = 2.2 V. d. PMOS: VGS = −2.5 V, VDS = −1.8 V.
Problem 1: The threshold voltage of the NMOS transmission gate transistor in the figure below is VTN = 0.4 V. Determine the output voltage vo for : a) vI = ϕ = 2.5 V b) vI = 1.8 V and ϕ = 2.5 V c) vI = 2.3 V and ϕ = 2.5 V d) vI = 2.5 V and ϕ = 1.5 V Neglect the body effect.
MOSFET as Resistor or Current Source: Assuming a threshold voltage of 0.5 V, determine whether each device is off, a resistor, or in saturation (current source). (a) (d) (g) (b) (e) (h) (c) (f) (i)
(25%) Problem 1. Figure 1 shows a 45 nmnMOS transistor. Assume Wn = 1 μm and Ln = 45 nm. Assume the body of the transistor is connected to ground, VB = 0 V. Figure 1 nMOS transistor a) Assume VD = VG = 1 V. Calculate the following;Drain current, IDSmall-signal parameters, gm and gdsOn-voltage (overdrive voltage), VoN b) Assume VD = 0.1 V and VG = 0.6 V. Calculate the drain current, ID c) Calculate CGs, CGD, and CDB for VD = VG = 1 V. Assume that body (substrate) of the transistor is grounded. (25%) Problem 2. Figure 2 shows an 18 nmnMOS finFET transistor. Assume nfin = 10. Assume the body of the transistor is connected to ground, VB = 0 V. a) Assume VD = VG = 1 V. Calculate the following;Drain current, IDSmall-signal parameters, gm and gdsOn-voltage (overdrive voltage), VoN b) Assume VD = 0.15 V and VG = 0.4 V. Calculate the drain current, ID c) Calculate CGS, CGD, and CDB for VD = VG = 1 V. Figure 2 nMOS finFET transistor
[Operating Region of MOSFET] Determine the region of operation for each of the enhancement MOSFETs and the flowing currents as shown in figure P-01. The transistors have threshold voltage, |VT| = 1 V and conductance constant, K = 0.15 mA/V2 (a) (b) Figure P-01. Operating Region of MOSFET
Exercise 4 VC, the voltage at C, transitions from 0 V to 1.8 V at t = 0. vC(t), the voltage across the capacitor, is 0 V at t = 0. VA = 1.8 V. Tasks: Is the switch on or off? Is A the source terminal or the drain terminal? What is the region of operation for the NMOS transistor at t = 0 ?
a. The diagrams below represents an NMOS connected to an output capacitor. The capacitor is charged from an initial 0V to VDD (5 V). i. Write an equation for the slope of the curve (terms of current and voltage). ii. Write an equation for the slope of the curve (terms of Rn). iii. Calculate Rn (W = 10, L = 2, VDD = 5 V, VTHN = 0.8 V & KPn = 120 uA/V2)
Exercise 2 VC, the voltage at C, transitions from 0 V to 1.8 V at t = 0. vC(t), the voltage across the capacitor, is 0 V at t = 0. VA = 0.9 V. Tasks:Is the switch on or off? Is A the source terminal or the drain terminal? What is the region of operation for the NMOS transistor at t = 0 ?
Part B - Calculate the drain current Consider the transistor circuit shown below. What is the drain current iD ? The threshold voltage is Vto = 1 V, K = 0.3 mA/V2, R1 = 10 Ω, and R2 = 40 Ω. Express your answer to three significant figures. Hints Submit My Answers Give Up
(21 pts total, 3 pts each) Determine the operating region and drain current for the following transistors. If the transistor is in saturation or triode, determine the drain voltage which is the boundary between those two regions. If the transistor is in cutoff, determine the gate voltage which is the edge of cutoff. The channel length is the minimum value. The NMOS width is 0.90 μm and the PMOS width is 1.8 μm. The channel length is 0.18 μm in all cases. Numerical answers to check your work: (a) drain voltage boundary = 0.727 V, ID = 295 μA (e) drain voltage boundary = 1.10 V, ID = 234 μA (a) (b) (c) (d) 0.6 V 1.0 V (f) (g)
Ideal P-Channel MOSFET IV Characteristics: (3 Points) For the following P-Channel, enhancement-type MOSFET. VT0 = −0.49 v k′ = 63 uA/V2 (notice the uA and the) W = 5 um L = 0.25 um λ = 0.05 a) Find IDS if: VG = 1.5 v VS = 2.5 v VD = 2.2 v VB = 2.5 v b) Find IDS if: VG = 1.5 v VS = 2.5 v VD = 0.5 v VB = 2.5 v c) Find IDS if: VG = 1.0 v VS = 2.5 v VD = 2.2 v VB = 2.5 v d) Find IDS if: VG = 1.0 v VS = 2.5 v VD = 0.5 v VB = 2.5 v
Problem 1: Determine the region of operation (e. g. , Cutoff, Linear, Blown-up, Triode, Ohmic, Resistive, Saturation, Forward-Active, Reverse-Active, etc. ) for each transistor below. For the NMOS and PMOS transistors, assume: L = 0.1 μm, W = 1.2 μm, |Vt0| = 0.4 V, |γ| = 0.4 V0.5, ϕf = 0.3 V, Ec = 1.5×106 V/m, and μCOX = 200 μA/V2.
V1 = 3.8 V : Is the MOSFET in triode or saturation? Calculate the drain current: V1 = 1.5 V : Is the MOSFET in triode or saturation? Calculate the drain current:
Determine the mode of operation (saturation, linear, or cutoff) and drain current ID for each of the biasing configurations given below. Use the following transistor data: NMOS: kn′ = 115 μA/V2, VT0 = 0.43 V, λ = 0.06 V−1 PMOS: kp′ = 30 μA/V2, VT0 = −0.4 V, λ = −0.1 V−1. Assume (W/L) = 1 and long-channel transistor models. a. NMOS: VGS = 2.5 V, VDS = 2.5 V PMOS: VGS = −0.5 V, VDS = −1.25 V. b. NMOS: VGS = 3.3 V, VDS = 2.2 V PMOS: VGS = −2.5 V, VDS = −1.8 V. c. NMOS:VGS = 0.6 V, VDS = 0.1 V PMOS: VGS = −2.5 V, VDS = −0.7 V.
Define the type of transistors and the region of operation (cut-off, linear, saturation) for each transistor. Assume Vdd = 3.3 V and thresholds VTn = |VTp| = 1.4 V. VDSATn = |VDSATp| = 1.0 V. Explain your answer. (a) (b) (c) (d)Consider an OAI321 static CMOS gate. (a) Draw the logic diagram (i. e. using AND/OR/INVERTER gates) (b) Draw the transistor schematic (using NFET/PFETs)
Question 2 The p-channel MOSFET circuit with terminal voltages is shown in Figure 1. Answer the following question by using device data given. μpCαt = 25 μA/V2, VTp = −1 V, γp = 0.6 V12, ϕn = 0.42 V, λp = (0.1/L)V−1 a. Label and indicate value for the source and the drain terminals. (2 marks) b. Identify in which region the transistor is operating. Prove your answer by showing the calculation. (7 marks) c. Find the drain current, ID. (4 marks) Figure 1 g. Content of assignment I. Calculation each step by step. II. Include the formula used.
The configuration shown below, an n-MOSFET with its drain and gate terminals connected together, is called a diode-connected MOSFET. a. In what mode does the MOSFET operate and why? b. Find the i−v characteristics of the two-terminal device in terms of the MOSFET parameters K and VT. c. Plot the i−v characteristics if K = 1 mA/V2 and VT = 1 V over the range of v = 0 to 5 V(1 V increments in voltage are sufficient)
QUESTION 6 Match the circuit symbols to the device type. A. 4-terminal PMOS B. 3-terminal PMOS C. 4-terminal NMOS D. 3-terminal NMOS
Problem 3.6 The threshold voltage of each transistor in Figure P3.6 is VTP = −0.4 V. Determin the region of operation of the transistor in each circuit. a) Cutoff b) Triode (Linear) c) Saturation a) Saturation b) Triode (Linear) c) Saturation a) Cutoff b) Saturation c) Triode (Linear) a) Triode (Linear) b) Saturation c) Cutoff (a) (b) (c) Figure P3.6
(7) Consider a depletion-mode MOSFET (shown in the figure) with Vpo = 6.00 V and IDSS = 2.00 mA. (a) [3 points] Identify the type of MOSFET. Select the one best choice. p-channel; n-channel. (b) [4 points] Consider the IV transistor characteristic iDS Vs. vDS. Identify the term for the region of operation for which current is constant (horizontal) with voltage. Select the one best choice. O Inactive Region; Active Region; Unsaturated Region; Saturated Region. (c) [6 points] Calculate the operating current iDS if vDS = +8.0 V and vGS = +1.0 V. iDS = (d) [6 points] Calculate the operating current iDS if vDS = +5.0 V and vGS = 0 V.
Determine the mode of operation for the following transistors. Assume that VTN = 1 V and VTP = −1 V. You do not need to show your work for this question. a) b)
Define the type of transistors and the region of operation (cut-off, linear, saturation) for each transistor. Assume Vdd = 3.3 V and thresholds VTn = |VTp| = 1.4 V. VDSATn = |VDSATp| = 1.0 V. Explain your answer. (a) (b) (c) (d)
Assume that the transistor shown below is described as follows: Kn = 4 mA/V2, VTN = 1 V. Make a graph of ID vs V2 for V1 = 0.5 V, 1.1 V and 1.2 V. On your graph, label the following:The modes of operation that the transistor is in Kn = 5000∗10^−6 Kn = 5000∗10^−6 Numerical values for Vdsat Values for the current when the transistor is in saturation
If Va = −3 V, and Vt = 3.1 V, what is the operating region of the n-channel MOSFET? Triode/ Ohmic region. Saturation region. Cut-off. None of the above. For example, if your transistor is operating in the saturation region then provide the integer 2 as your answer. For cases like VGS = VT, answer 4.
Calculate the drain current (ID) in an NMOS transistor. VDD = 3 V, VG = 7 V, RG = 3 kΩ, Kn = 0.2 mA/V2 and Vtn = 1.0 V. Write down the answer only (You don't need to show me your calculation).
(12 pts) For each of the drawings below, determine the device type (NMOS or PMOS) and which region the transistor is operating in (Cutoff, Triode, or Saturation) Assume that |Vt| = 1 V. You must justify your answer to receive credit! 1.5 V −0.5 V
Q4. Determine the mode of operation and drain current IDs for each of the biasing configuration with tox = 4.1 nm, εox = 3.97∗εo F cm, ε0 = dielectric constant of vacuum. Use the following transistor data: [20 pt] NMOS: μn = 175.24 cm2 V2 sc, VT0 = 0.7 V, λ = 0.1 V−1, WL = 2 PMOS: μp = 58.14 cm2 Vsec, VT0 = −0.8 V, λ = 0.1 V−1, WL = 2 a. NMOS: VGS = 2.1 V, VDS = 3.3 V, VBS = 0 [4 pt] b. NMOS: VGS = 3.3 V, VDS = 2.1 V, VBS = 0 [4 pt] c. NMOS: VGS = 0.6 V, VDS = 3.3 V, VBS = 0 [4 pt] d. PMOS: VGS = −2.2 V, VDS = −3.3 V, VBS = 0 [4 pt] e. PMOS: VGS = −3.2 V, VDS = −2.3 V, VBS = 0 [4 pt]
Problem 7) The MOSFET of the previous problem is connected to a circuit in the following way:Drain and source terminals connected to a Thévenin circuit consisting of voltage source VDD = 10 V and series resistance RD = 2.5 kΩ. Gate and source terminals connected to a voltage source vIN = 8 V. c) What are the values of vDS and iD for the MOSFET? d) In what region does the MOSFET operate? Problem 8) For the MOSFET and circuit of the previous problem, suppose that vN is changed in a continuous way from 0 V to 9 V. Plot vDS as a function of vIN.
What are the conditions to keep our transistor in saturation, linear, and cut-off regions? Why is los very low at lower VGS even if VDS is pretty high? Write down the step by step methods to extract gds from the measured value. Why is the following circuit called diode-connected? Why do we need to provide negative voltage (VG, VD) instead of positive (for pmos)?
Determine the region of operation for each of the enhancement transistors and the currents shown in the picture given below. The transistors have |Vto| = 1 V and K = 0.1 mA/V2. (a) (c) (b) (d) Select one: a. Transistor b: PMOS operating in saturation region with Ib = 0.4 mA, b. None of the answers c. Transistor a: NMOS operating in triode region with Ia = 0.9 mA, d. Transistor c: NMOS operating in triode region with Ic = 0.7 mA, e. Transistor d: NMOS operating in triode region with Id = 0.7 mA,
In circuit below, a 0.18 μm technology NMOS is used for which tox = 4 nm, μn = 450 cm2/V⋅s, VTn = 0.7 V and W/L = 20 : a. Identify the source, drain, gate, and bulk terminals . b. find Cox, kn. c. Determine the transistor mode of operation and the current ID in the transistor . d. If the voltage source 0.2 V was increased such that the transistor is operating in saturation . what would be the Minimum value of the voltage source ? Determine the value of the current for this case?
Consider the following MOSFET characteristics. What type of device is it? A. N-channel depletion-mode MOSFET. B. N-channel enhancement-mode MOSFET. C. P-channel depletion-mode MOSFET. D. P-channel enhancement-mode MOSFET.
The ID-VGs curves shown in Fig. 2 correspond to (circle one) (a) A = n-channel depletion-type FET, C = p-channel enhancement-type FET (b) all depletion-type FETs (c) B = depletion-type FET, C = enhancement-type FET (d) A = n-channel FET, B = p-channel FET (e) none of the above options. Figure 2
Question 1: Give an expression and find the value for the output voltages for the pass transistor networks shown in Figures. Neglect the body effect. Kn, p = 0.5 mA/V2, VTn = 1 V, VTpp = −0.5 V, and VDD = 5 V. (a) (b) (c) (d) (a) Vout = (b) Vout = (c) Vout = (d) Vout =
P R O B LEM 6.3 Consider a family of logic gates that operate under the static discipline with the following voltage thresholds: VOL = 1 V, VIL = 1.3 V, VOH = 4 V, and VIH = 3 V. Consider the N-input NAND gate design shown in Figure 6.63 . In the design R = 100 k and RON for the MOSFETs is given to be 1 k. VT for the MOSFETs is 1.5 V. What is the maximum value of N for which the NAND gate will satisfy the static discipline? What is the maximum power dissipated by the NAND gate for this value of N ? FIGURE 6.63
Q5: (5 mrks) a) (2 Pts) Suppose VDD = 2.2 V and Vt = 0.4 V. Determine Vout in Fig. P5. a for: i. Vin = 0(1 mrk) ii. Vin = 1.2 V(1 mrk) Fig. P5. a Answer. b) (1 Pts) Write the expression of Vout in Fig. P5. b. Answer. Fig. P5. b c) (2 Pts) On each transistor write the value of VS
Problem 1. The output of an nFET is used to drive the gate of another nFET as shown in the following figure. Assume that VDD = 5.0 V and VTn = 0.50 V. Find the output voltage Vout when the input voltages are at the following values ( 30 points). (a) Va = 5.0 V and Vb = 5.0 V; (b) Va = 0.4 V and Vb = 3.0 V; (c) Va = 2.0 V and Vb = 2.5 V; (d) Va = 5.0 V and Vb = 1.8 V;
The technology parameters are: λ(NMOS) = λ(PMOS) = 0 V−1;γ = 0, VDD = 3.3 V, VTH(NMOS) = |VTH (PMOS)| = 0.5 V, μnC0 x = 0.1 mA/V2, μpCox = 0.05 mA/V2, and C0 x = 5 fF/μm2. Assuming the transistor sizes are: L1 = 0.5 μm, L2 = 4 μm, W1 = 5 μm, and W2 = 20 μm, and furthermore, Vbies = 0.8 V : a) What is the region of operation of each transistor? [8 marks] b) If the input signal, Vin , is a step function with a small magnitude of 10 mV (i. e. , Vin abruptly changes from 0 V to 10 mV at time t = 0 ), what is Vout (t) for t ≥ 0 ? [12 marks] Note: If you need to consider a device capacitance, only take into account the gate
Assuming the capacitor is initially discharged, |Vt|−1 V, and the NMOS is open circuit in cut-off region. If Vx is increased from 0 to 4.7 Volts, enter the steady state value of Vo in Volts
Give an expression for the output voltage for the pass transistor networks shown below. Neglect the body effect. (a) (b) (c) (d)
carefully from t = −∞ to t = +∞. Is this a strong or a weak transfer? Explain. Which side of the Pass-transistor is the Source and which side is the Drain at t = −∞ ? Explain.
a. A MOS inverter has the transfer characteristics shown in Figure 1. i. Estimate if the inverter is of NMOS, PMQS or CMOS, justify the reason. (3 Marks) ii. What are the values of VIL, VIH, VOL, and VOH that give best noise margins? Mark them on the characteristics. (8 Marks) iii. What are these high and low noise margins? (2 Marks) Figure 1 for the pass transistor network shown in Figure 2.a and 2.b (10 Marks) Figure 2.a Figure 2.b
For the pass-transistor circuit having vI as input and vO as output shown below: (a) If initially vO = 0 and then vI is raised to VDD, what is the final value of VOH ? (b) If initially vO = VDD and then vI is lowered to 0 , what is the final value of VOL ?
(b) For the pass-transistor circuits shown below, answer the following questions 1 - 4. Assume VDD, GND as power supplies and |Vtp| and Vtn as the threshold voltages of pMOS and nMOS respectively. In the above figure, the output voltage for the pass-transistor circuit in (a) is In the above figure, the output voltage for the pass-transistor circuit in (b) is In the above figure, the output voltage for the pass-transistor circuit in (c) is In the above figure, the output voltage for the pass-transistor circuit in (d) is A 2-input NOR gate is designed to achieve the effective rise and fall time of a unit inverter. What is the value of k for the pMOS transistors? What is the value of k for the nMOS transistor in the 2 -input NOR gate in the above problem?
Problem 2 (30 points): a) In the first family of curves plot, identify the triode and saturation regions, i. e. create a curve that divides the MOSFET response into these two regions. b) From the first family of curves plot, identify the MOSFET parameters, VTN and K. c) Using both plots, estimate the Early voltage, VA. Family of Curves, VA = 0 V Family of Curves with VA > 0 V
The circuit configuration shown below is commonly used for measuring n-channel MOSFET parameters. You are given the MOSFET parameters λ = 0 V−1 L = 1 μm W = 1 μm Use the accompanying graph (note: it is the square root of drain current vs. gate voltage) to A. (10 pts) estimate the threshold voltage of the n-channel MOSFET; B. (10 pts) calculate the transconductance parameter, kn'.
The drain characteristics in the linear portion of the ohmic region for a certain idealized n-channel enhancement-mode MOSFET are shown below. Determine the values of conductance and resistance for each of the following values of VGS:( (a) +8 V; (b) +10 V; (c) +12 V. gDS = ΔID ΔVDS rDS = 1 gDS The overall drain characteristics of the idealized MOSFET of Problem 1 are shown below. (a) Determine the gate-source threshold voltage and the pinch off voltage. (b) Determine the transition voltage (from ohmic to beyond cutoff regions) for the following values of VGS:7 V, 9 V, 11 V. ID = K(VGS VGS(th) − 1)2 VP = VGS(th) VDS(tran) = VDS − VP Refer to the idealized n-channel enhancement-mode MOSFET characteristics of the figure above. (a) Determine the values of K and VGS(th). (b) Write an equation for ID in the beyond-pinchoff region. (c) Verify that the result of (b) predicts the correct values of current for VGS = +8 V, +10 V, and +12 V.
Question 3. The output characteristic of a MOSFET are shown in Fig. 5. Figure 5. Family of I−V curves for a MOSFET' Answer the following questions regarding the transistor. (1) Is this a PMOS or a NMOS transistor? (2) Is this an enhancement-mode or depletion-mode transistor? (3) What are the values of k and VT for this transistor?
The following figure is the ID−VD characteristics of a NMOSFET with Tox = 10 nm, W = 8 μm, and L = 2 μm. (Assume m = 1 and ignore velocity saturation. ) (a) Estimate VTH from the plot. (b) Estimate μn in the inversion layer. (c) Add the I−V curve corresponding to VGS = 3 V in the plot above.
Extracting Parameters for the Unified Model Below are the I-V curves for an NMOS transistor: In this problem, the objective is to use a transfer curve like the one above to obtain information about the transistors. The transistor has (W/L) = (5 /1). You may also assume that velocity saturation does not play a role in this example. Also assume 2ϕF = −0.6 V From the figure above, determine the following parameters: VTo, γ, λ.
Transistors can complement each other. A pair of Si transistors have the output characteristics shown in the graph below. Both transistors have a gate length of 1 μm and a gate width of 10 μm and the gate oxide is SiO2 (dielectric constant, εox = 3.9 ). a. Identify on the figure which is PMOS and which is NMOS. b. From a plot of IDS vs. VGS, determine the threshold voltages and transconductances at |VGS| = 2 V of both transistors. c. What is the oxide thickness for both transistors? For this use the mobility values at low doping density.
Problem 6) A MOSFET has the i−v characteristics shown below. Find the following parameters: Find the approximate values of threshold voltage VTR and conductance parameter K.
I-V characteristics of a MOSFET with xo = 10 nm, Z = 10 μm, and L = 2 μm are shown below. Considering simply the square-law theory (a) Estimate VT from the plot (b) Estimate the effective mobility in the channel and explain (c) Estimate the gate bias for the bottom curve and explain
Consider the circuit configuration shown below, which is commonly used for measuring n-channel MOSFET parameters. The transistor's length and width are 1 μm. The accompanying graph plots the transistor's square root of drain current vs. gate voltage, VG. a) Estimate the threshold voltage of the n-channel MOSFET. b) When VG is between 1.5 V and 2.5 V, in what region is the device operating? Consider the p-channel MOSFET amplifier given to the right. ID = 12 kp(VSG − |Vtp|)2, VDD = 5 V, RL = 2 kΩ, kp = 1 mA/V2, Vtp = −1 V c) Derive an expression for the transistor bias point, VGQ, as a function of VDD, Ra, and Rb. d) Determine the required ratio Ra/Rb such that the MOSFET current, ID = 0.5 mA e) What is the voltage bias point of the output VoutQ? Use the value(s) from part d. Please show all steps. A_ = 0.5 VB = Saturation C = VoD(Rb/(Ra+Rb))D = Ra/Rb = 2/3 E = 1 V)
A) The measured ID versus VDS characteristic of the two MOSFETs are shown in Figure 1. a. On Figure 1 A, clearly label the Triode and Saturation Region of operation? (4 points) Figure 1 A Figure 1 B b. What are the output resistances of M1 and M2 in saturation? c. What are the Ron of M1 and M2 in the triode region?
Problem 2: Regions of Operation (a) Determine the different operation mode of the device while V0 is changed from 0 to Vdd. Derive the condition for V0 at the boundary of each operation mode using the unified short channel MOS model. Calculate the boundary values of V0. Assume Vdsat does not change with Vt. Vdd = 1 V, Vt0 = 0.33 V, kγ = 0.1 V/V ( linear body effect coefficient), Vdsat = 0.55 V, λ = 0 V−1, k′ = μnCox = 30∗10−6 A/V2, W/L = 300 nm/100 nm (b) What are the values of Ids for V0 = Vdd and V0 = 0.5 V dd. You do NOT need to simplify (e. g. , you can just list the expressions such as A/B∗10−x or A∗(B−C)∗10−x).
Problem 3. Saturation Region Current-Voltage Characteristics [10 points] Fig. P3 The PMOS transistor has Vtp = −0.5 V, kp′ = 200 μA/V2, and λp = 0.1 V−1. (a) Depict a set of ID−VS characteristic curves with (W/L) = 10 and 20 for this PMOS transistor operating in the saturation region. Please clearly label ID for VS = 0.5 V, 1.0 V, 1.5 V, and 2.0 V on these two curves. Although only a sketch, the diagram should be drawn to scale as much as possible. (b) Find r0 of the PMOS transistor for VS = 2.0 V with (W/L) = 10 and 20, respectively (Hint: please follow the ro definition shown in Lecture 2, Page 27).
Consider a p-channel enhancement mode MOSFET biased as shown in the following figure. Sketch the current-voltage characteristics ( ID vs. VD ) for: (a) VGD = 0; (b) VGD = VT/2; (c) VGD = 2VT.
For the following NMOS we have: Vs is grounded but both VD and VG are variable but at all times: VGS > Vth Which of the following statements are correct? This NMOS is working in Triode region of operation If this MOSFET worked in Saturation and we start reducing VD, the length L1 starts increasing If this MOSFET operated exactly at the edge of saturation/triode then: L1 = L
FET is basically a voltage-controlled current-amplifier device, in which Drain Current ( ID ) is controlled by the voltage between Gate and Source ( VGS). The following figures show different types of Field Effect Transistors ( FET ). Identify (i.e., name) the FET type for each of the figures. Explain how ID is controlled in terms of the VGS and the channel width variations for each FET type. (a) (b) (c) Source
An N-MOSFET having Vt = 1 V is operated in the triode region with vDS small. With vGS = 1.5 V is found to have a resistance rDS = 1180 Ω. a. What value of VGS is required to obtain rDS = 200 Ω. b. With the previously computed value of VGS, compute the resistance rDS if the device's W is doubled. Note: In this problem, you may only submit numerical answers accurate to 0.02% or better. (i. e. If 4 is the correct answer, 3.9999 will be marked as correct, but 2+2 will be marked as incorrect. ) (a) VGS: V (b) rDS : Ω
Suppose a battery VB > 0 is connected between the gate and drain of an ideal n-channel MOSFET as in the figure below. Using the ideal ID−VDS characteristics (square law) (a) Find the relation between ID and VDS(VDS > 0) and sketch your result, if VB = VT/2. ( 5 points) (b) Find the relation between ID and VDS(VDS > 0) and sketch your result, if VB = 2VT. ( 5 points)
Device Level A cross section view of an MOS device is shown in Figure 1. (a) What type is this device (NMOS or PMOS)? (b) Considering the potential of each terminal in this figure, determine Source, Drain, Gate, and Substrate terminals and label them on the diagram. (c) Assuming that |Vt| = 0.5 V and VDSat = 1 V. Find the region of operation of the device (cutoff, linear, saturation, or velocity saturation). Ignore body effect. (d) Determine drain current if |K′|(W/L) = 1 mA/V2, (W/L) = 10, and |λ| = 0.1 V−1. Figure 1 Biased MOSFET Transistor
5- (20 points) Calculate the drain current and source to drain voltage of a common source circuit with a p-channel enhancement mode MOSFET. Consider the circuit shown. Assume R1 = R2 = 50 KΩ, VDD = 5 V, RD = 7.5 KΩ, VTP = −0.8 V, and Kp = 0.2 mA/V2.
6- (20 points) Figure shows a common-source MOSFET amplifier using RG for biasing purposes. Determine this circuit's small-signal voltage gain. Vt = 1.5 V, K = 0.125 mA/V2. Assume the coupling capacitors to be sufficiently large so as to act as short circuits at the signal frequencies of interest.