Question

Notify Me Bookmark

An nMOS transistor has a threshold voltage of 0.4 V and a supply voltage of VDD = 1.2 V. A circuit designer is evaluating a proposal to reduce VDD by 100 mV to obtain faster transistors. a) By what factor would the saturation current increase (at Vgs = Vds = VDD) if the transistor were ideal? b) By what factor would the subthreshold leakage current increase at room temperature at Vgs = 0? Assume n = 1.4. c) By what factor would the subthreshold leakage current increase at 120 deg C? Assume the threshold voltage is independent of temperature.

An nMOS transistor has a threshold voltage of 0.4 V and a supply voltage of VDD = 1.2 V. A circuit designer is evaluating a proposal to reduce VDD by 100 mV to obtain faster transistors. a) By what factor would the saturation current increase (at Vgs = Vds = VDD) if the transistor were ideal? b) By what factor would the subthreshold leakage current increase at room temperature at Vgs = 0? Assume n = 1.4. c) By what factor would the subthreshold leakage current increase at 120 deg C? Assume the threshold voltage is independent of temperature.

Image text
An nMOS transistor has a threshold voltage of 0.4 V and a supply voltage of VDD = 1.2 V. A circuit designer is evaluating a proposal to reduce VDD by 100 mV to obtain faster transistors. a) By what factor would the saturation current increase (at Vgs = Vds = VDD) if the transistor were ideal? b) By what factor would the subthreshold leakage current increase at room temperature at Vgs = 0? Assume n = 1.4. c) By what factor would the subthreshold leakage current increase at 120 deg C? Assume the threshold voltage is independent of temperature.

Detailed Answer

1 0

Please enter your email here. You will get email when this question is answered by our tutor.

Answer
Doubtrix Logo

This Problem has been solved!

You'll get a detailed, step-by-step and expert verified solution.

Join Doubtrix with 7-days free trial

  • Icon Correct & Verified Answers
  • Icon No AI-Generated Answers
  • Icon Video Solution for Difficult Questions
  • Icon Work With Experts to Reach at Correct Answers
Login Sign Up
  • Student Reviews:
  • (1)
  • Correct answers (1)
  • Complete solution (1)
  • Step-by-step solution (1)
  • Fully explained (1)

Similar/Related Questions

An NMOS transistor has a threshold voltage (Vth) of 0.4 V and operates at a supply voltage (Vdd) of 1.2 V. A circuit designer is evaluating a proposal to reduce the threshold voltage Vth by 100 mV to obtain faster transistors. (i) By what factor would the saturation current increase (at Vgs = Vds = VDD ) if the transistors were ideal? (ii) By what factor would the subthreshold leakage current increase at room temperature at Vgs = 0 ? Assume n = 1.3 and vT = 26 mV. (Read Section 2.4.4 of your textbook.)

Solution
0 0

The subthreshold leakage current in an NMOS transistor is given by the following expression: iD = ISe^VGS/nVT. The constant value IS in this expression is proportional to e-Vt/nVT (Do not confuse Vt with VT, Vt is the threshold voltage value and V, is the thermal voltage value). Assume n = 2, if the threshold voltage of an NMOS transistor is reduced by 0.1V, by what factor the static power dissipation increase?
Solution
1 0

In this amplifier circuit, the high and low DC voltage sources are: VDD = 5 V and VSS = −5 V respectively. Consider that all three external capacitors have high values. The PMOS transistor has a threshold voltage equal to Vt = −1 V and kp = kp′(W/L) = 0.4 mA/V2, and the NMOS transistor has a threshold voltage Vt = 1 V and a kn = kn′(W/L) = 2 mA/V2. It was shown in HW#7 that the DC drain voltage of the PMOS transistor is −0.2 V and the DC source of the NMOS transistor is −2 V. a) Perform the small signal analysis of this circuit and determine the voltage gain: AV = Vo/Vi b) Determine the input and output resistance of this amplifier Rin and Rout . c) Discuss what is the purpose of the part of the circuit between CC2 and CC3 which includes the NMOS transistor in this amplifier design. d) Determine the parameters of a simple voltage amplifier model (discussed in chapter 1) which will represent this amplifier. Note that the parameters of the simple voltage amplifier excludes any series resistance of the external source ( Vi ) (in this case it is zero anyway) and the load resistance (in this case RL = 2 kΩ ). e) Using the simple model from part (c) determine the voltage gain AV = Vo/Vi and see if it agrees with the answer of part (a). VDD
Solution
0 0