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Assignments Week 1 CMOS

The document contains 6 questions analyzing the characteristics and performance of a CMOS inverter circuit. It asks the student to derive expressions, explain DC characteristics with diagrams, discuss how the switching point varies with transistor ratios, calculate voltages and times for different loads, and find the maximum operating frequency. It also asks how to improve the noise margin.

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SHREYAS MAGAJIKONDI
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160 views1 page

Assignments Week 1 CMOS

The document contains 6 questions analyzing the characteristics and performance of a CMOS inverter circuit. It asks the student to derive expressions, explain DC characteristics with diagrams, discuss how the switching point varies with transistor ratios, calculate voltages and times for different loads, and find the maximum operating frequency. It also asks how to improve the noise margin.

Uploaded by

SHREYAS MAGAJIKONDI
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Assignment_Week_1: Analysis of CMOS Inverter

1. Derive the expression for the switching point of a CMOS inverter


2. Explain the DC characteristics of a CMOS inverter with necessary diagrams.
3. Discuss the variation in switching point of a CMOS inverter with changes in βp/βn ratio.
4. Find the ratio βp⁄βn needed to obtain an inverter midpoint voltage V M=1.3V with power supply
of VDD=3V. Assume that VTn=0.6V and VTp=-0.82V. What would be the relative device size if
K’n=110µA/V2 and the mobility values are related by µn=2.2µp. Also find the relative widths of
MOS devices.
5. An inverter uses FETs with β n=2.1 mA/V2 and βp=1.8 mA/V2. The threshold voltages are given
as VTn=0.6V & VTp=-0.7V & the power supply has a value of V DD=5V. the parasitic FET
Capacitance at the output node is estimated to be CFET = 74 fF.
a) Find the mid-point voltage VM.
b) Find the values of Rn & Rp.
c) Calculate the rise & fall times at the output when CL=0, and when CL=115fF.
d) Plot tr & tf as a function of CL
e) Find the maximum frequency of operation
6. Calculate the noise margin for a CMOS inverter operating at 3.3V with V tn=0.7V, Vtp=-0.7V,
βp=βn. What would you do to the transistor characteristics to improve the noise margin?

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