How to Analyse the Cmos Buffer With Two transistors
This is one of the most prominent questions that is often asked in technical interviews of any electronics company.
This circuit seems like it is very simple,but it if you start solving it it will lead to hell.
In this post I will analyse this circuit and plot the VOUT vs VIN characteristics same as like the CMOS inverter.
I will give a few steps for users who are new.
step1:
Draw the Ids Vs vds Characteristics of PMOS.
Step2:
Draw the Ids Vs Vds charecteristics of NMOS.
Step3:
Overlap both the characteristics in a single plot.
Step4:
Find the Intersections Between the two plots for different values of Vgs.
These Values will give you the input and output values that are being satisfyied by the circuit. As it is very tuff to say intutively that which transistor will On and which will off for which values of input because those conditions will include the output voltage,I use MATLAB to get these graphs and intersections. The Matlab Code is given Below: clc; clear all; close all; vdd=5; up=500; un=1500; cox=3.28e-6; wbyl=2; wbylp=6; vtn=0.5; vtp=-0.5; vin=0:0.1:5; vout=0:0.01:5; lengthofvin=length(vin); lengthofvout=length(vout); for j=1:lengthofvin for i=1:lengthofvout if (vin(j)-vout(i)) < vtn currentn(j,i)=0; end if (vdd-vout(i))>(vin(j)-vout(i)-vtn)&& (vin(j)-vout(i))>=vtn currentn(j,i)=0.5*un*cox*wbyl*((vin(j)-vout(i)-vtn).^2); end if (vdd-vout(i))<=(vin(j)-vout(i)-vtn )&& (vin(j)-vout(i))>=vtn currentn(j,i)=un*cox*wbyl*(vin(j)-vout(i)-vtn-(vdd-vout(i))./2).*(vdd-vout(i)); end end end for j=1:lengthofvin for i=1:lengthofvout if (vout(i)-vin(j)) < abs(vtp) currentp(j,i)=0; end if (vout(i))>(vout(i)-vin(j)-abs(vtp))&& (vout(i)-vin(j))>=abs(vtp) currentp(j,i)=0.5*up*cox*wbylp*((vout(i)-vin(j)-abs(vtp)).^2); end if (vout(i))<=(vout(i)-vin(j)-abs(vtp)) && (vout(i)-vin(j))>=abs(vtp) currentp(j,i)=up*cox*wbylp*(vout(i)-vin(j)-abs(vtp)-((vout(i))./2))*(vout(i)); end end end hold on; plot(vout,currentp','b'); xlabel('--------->vds'); ylabel('--------->ids'); title('Ids Vs Vds'); plot(vout,currentn','r'); hold off; for j=1:lengthofvin count=0; for i=1:lengthofvout if currentn(j,i)==currentp(j,i) newinput(1,j)=vin(j); if(vout(i)<=abs(vtp)) newoutput(1,j)=abs(vtp); else if(vout(i)>=vdd-vtn) newoutput(1,j)=vdd-vtn; end newoutput(1,j)=vout(i); count=count+1; if count==1 break; end end end end end for j=1:lengthofvin count=0; for i=lengthofvout:-1:1 if currentn(j,i)==currentp(j,i) newoutput1(j,1)=vout(i); if(vout(i)>=vdd-vtn) newoutput1(j,1)=vdd-vtn; end count=count+1; if count==1 break; end end end end figure; hold on; plot(newinput,newoutput,'b',newinput,newoutput1,'b'); axis([0 5 0 5]); xlabel('--------------->vin'); ylabel('--------------->vout'); title('Transfer Characteristics');
The plot of the above MATLAB code will look something like give below:
So in the graph you can see that the intersection of the PMOS and NMOS curves for a particular value of VGS are the input and output voltages that will satisfy this circuit conditions.And from the above plot it is clear that we can see a lot of intersections between the PMOS and NMOS curves .So let us consider the average value of voltage between the first point of intersection and the last point of intersection between the two PMOS and NMOS curves for a particular value of VGS. Then we will get the input versus output characteristics as shown below.But still we have a confusion because we took an average intersection point .
If we take the first intersection point ,then we will get the characteristics like shown below:
One of the most important question that is often asked in an interview(IT company)
These are all questions you've probably heard or even asked yourself. The term "cloud computing" is everywhere.
In the simplest terms, cloud computing means storing and accessing data and programs over the Internet instead of your computer's hard drive. The cloud is just a metaphor for the Internet. It goes back to the days of flowcharts and presentations that would represent the gigantic server-farm infrastructure of the Internet as nothing but a puffy, white cumulonimbus cloud, accepting connections and doling out information as it floats.
What cloud computing is not about is your hard drive. When you store data on or run programs from the hard drive, that's called local storage and computing. Everything you need is physically close to you, which means accessing your data is fast and easy, for that one computer, or others on the local network. Working off your hard drive is how the computer industry functioned for decades; some would argue it's still superior to cloud computing, for reasons I'll explain shortly.
The cloud is also not about having a dedicated network attached storage (NAS) hardware or server in residence. Storing data on a home or office network does not count as utilizing the cloud. (However, some NAS will let you remotely access things over the Internet, and there's at least one NAS named "My Cloud," just to keep things confusing.)
For it to be considered "cloud computing," you need to access your data or your programs over the Internet, or at the very least, have that data synchronized with other information over the Web. In a big business, you may know all there is to know about what's on the other side of the connection; as an individual user, you may never have any idea what kind of massive data-processing is happening on the other end. The end result is the same: with an online connection, cloud computing can be done anywhere, anytime.
UNIX is an operating system which was first developed in the 1960s, and has been under constant development ever since. By operating system, we mean the suite of programs which make the computer work. It is a stable, multi-user, multi-tasking system for servers, desktops and laptops.
UNIX systems also have a graphical user interface (GUI) similar to Microsoft Windows which provides an easy to use environment. However, knowledge of UNIX is required for operations which aren't covered by a graphical program, or for when there is no windows interface available, for example, in a telnet session.
Types of UNIX
There are many different versions of UNIX, although they share common similarities. The most popular varieties of UNIX are Sun Solaris, GNU/Linux, and MacOS X.
Here in the School, we use Solaris on our servers and workstations, and Fedora Linux on the servers and desktop PCs.
The UNIX operating system
The UNIX operating system is made up of three parts; the kernel, the shell and the programs.
The kernel
The kernel of UNIX is the hub of the operating system: it allocates time and memory to programs and handles the filestore and communications in response to system calls.
As an illustration of the way that the shell and the kernel work together, suppose a user types rm myfile (which has the effect of removing the filemyfile). The shell searches the filestore for the file containing the program rm, and then requests the kernel, through system calls, to execute the program rm on myfile. When the process rm myfile has finished running, the shell then returns the UNIX prompt % to the user, indicating that it is waiting for further commands.
The shell
The shell acts as an interface between the user and the kernel. When a user logs in, the login program checks the username and password, and then starts another program called the shell. The shell is a command line interpreter (CLI). It interprets the commands the user types in and arranges for them to be carried out. The commands are themselves programs: when they terminate, the shell gives the user another prompt (% on our systems).
The adept user can customise his/her own shell, and users can use different shells on the same machine. Staff and students in the school have thetcsh shell by default.
The tcsh shell has certain features to help the user inputting commands.
Filename Completion - By typing part of the name of a command, filename or directory and pressing the [Tab] key, the tcsh shell will complete the rest of the name automatically. If the shell finds more than one name beginning with those letters you have typed, it will beep, prompting you to type a few more letters before pressing the tab key again.
History - The shell keeps a list of the commands you have typed in. If you need to repeat a command, use the cursor keys to scroll up and down the list or type history for a list of previous commands.
Files and processes
Everything in UNIX is either a file or a process.
A process is an executing program identified by a unique PID (process identifier).
A file is a collection of data. They are created by users using text editors, running compilers etc.
Examples of files:
a document (report, essay etc.)
the text of a program written in some high-level programming language
instructions comprehensible directly to the machine and incomprehensible to a casual user, for example, a collection of binary digits (an executable or binary file);
a directory, containing information about its contents, which may be a mixture of other directories (subdirectories) and ordinary files.
The Directory Structure
All the files are grouped together in the directory structure. The file-system is arranged in a hierarchical structure, like an inverted tree. The top of the hierarchy is traditionally called root (written as a slash / )
In the diagram above, we see that the home directory of the undergraduate student "ee51vn" contains two sub-directories (docs and pics) and a file called report.doc.
The full path to the file report.doc is "/home/its/ug1/ee51vn/report.doc"
Starting an UNIX terminal
To open an UNIX terminal window, click on the "Terminal" icon from Applications/Accessories menus.
An UNIX Terminal window will then appear with a % prompt, waiting for you to start entering commands.
The foundation of the TATA group was laid by JamsetjiNusserwanji Tata in 1868, exactly 100 years before TCS was founded.
In 1938, JRD Tata was appointed as the chairman who led the TATA Group for next 53 years. During his time, TATA Group expanded regularly into new spheres of business. The more prominent of these ventures were Tata Chemicals, Tata Motors, Tata Industries, Voltas, Tata Tea, Tata Consultancy Services and Titan Industries.
In early ninety (1991), Ratan Tata took over as chairman of the TATA Group. Under his stewardship, Tata tea acquired Tetley, Tata Motors acquired Jaguar Land Rover and Tata Steel acquired Corus, which have turned the TATA Group from a largely India-centric company into global business. Ratan Tata retired from all executive responsibility in the TATA Group in December 2012 and he is succeeded by Cyrus Mistry, the present Chairman.
To learn about more about the Tata Group's 150+ years of history, please click on Tata Group History.
About TCS
Company Overview
Tata Consultancy Services is an IT services, consulting and business solutions organization that delivers real results to global business, ensuring a level of certainty no other firm can match.
All above figures as of Sep 2013
Tata Consultancy Services is an IT services, consulting and business solutions organization that delivers real results to global business, ensuring a level of certainty no other firm can match. TCS offers a consulting-led, integrated portfolio of IT, BPO, infrastructure, engineering and assurance services. This is delivered through its unique Global Network Delivery Model, recognized as the benchmark of excellence in software development. A part of the Tata Group, India's largest industrial conglomerate, TCS has over 276,196 of the world's best trained consultants in 44 countries. The Company generated consolidated revenues of US $ 11.57 billion for year ended 31 March, 2013 and is listed on the National Stock Exchange and Bombay Stock Exchange in India.
Experience Certainty
Tata Consultancy Services helps customer experience certainty by reliably delivering business results, providing leadership to drive transformation and partnering for success.
Your dedicated team will have domain and technology capabilities resulting in specialized services / solutions
Our engagement models are uniquely flexible, enabling design that fits the size and scale of your operations
You have access to partnership gain-share and risk-share models focused on your success
Your inputs and our expertise are merged through our Centers of Excellence (COEs) to deliver leading solutions
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Our unique delivery model offers multiple levers of time zone, language, skills and local business knowledge to deliver high quality solutions across the globe, 24x7
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Comprehensive 360o interconnected research ecosystem with 19 labs worldwide
Collaborate with a wide network of partners, institutions and venture capitalists on forward-looking solutions
Your business innovation is fueled by our dedicated labs on advanced and emerging technology trends and scientific research Co-Innovation Network (COIN)TM
(COIN)TM is a rich and diverse network that drives innovation in an open community
World's first organization to achieve an enterprise-wide Maturity Level 5 on both CMMI(R) and P-CMM(R), using SCAMPI(SM), the most rigorous assessment methodology.
TCS Mission
To help customers achieve their business objectives by providing innovative, best-in-class consulting, IT solutions and services.
To make it a joy for all stakeholders to work with us.
TCS Values
Leading change
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TCS Executive Profile
Chairman: Cyrus Mistry
Chief Executive Officer (CEO) and Managing Director (MD): N. Chandrasekaran
Chief Financial Officer (CFO): Rajesh Gopinathan
Head – Global Human Resource: Ajoyendra Mukherjee
Chief Technology Officer (CTO): K Ananth Krishnan
TCS Process Excellence
ISO27001 – Helps organization strengthen its information security policies and processes
ISO14001 – Helps organization strengthen its environment policies and processes
OHSAS18001 – Helps organization strengthen its health and safety policies and processes
CMM Level 5 – Helps organization to manage and optimize its processes
PCMM – Helps organization to continuously improve the management and development of its human resources
ISO 9000 family – Helps organization strengthen its quality management system
Services
TCS helps clients optimise business processes for maximum efficiency and galvanise their IT infrastructure to be both resilient and robust. TCS offers the following solutions:
TCS has the depth and breadth of experience and expertise that businesses need to achieve business goals and succeed amidst fierce competition. TCS helps clients from various industries solve complex problems, mitigate risks, and become operationally excellent. Some of the industries it serves are:
In year 2012, TCS has bagged many awards in different sectors. Listed below some of the achievements but the list is endless.
I. BT 500 ranks TCS as the most valuable company of 2012
TCS was ranked as the most valuable company of 2012 in the BT 500 list that was released recently. This is the first time that our company has emerged on top of this rankings list released each year by the Business Today magazine. The issue dated November 11, 2012 credits CEO N. Chandra for much of this success. Click here to read CEO Chandra’s interview.
II. N. Chandra wins Best CEO of the Year award at Forbes India Leadership Awards
CEO & MD, N. Chandra won the Best CEO of the Year award at the Forbes India Leadership Awards 2012. He was presented this award at a function held in Mumbai on 28 September 2012. Our CEO won the honour ‘for being able to balance aggression needed to achieve stretched goals, with conservatism and for building a solid team for next generation of managers.
III. CEO & MD, N Chandra, won CNBC’s ‘Asian Business Leader of the Year’
N. Chandra won the Asian Business Leader of the Year award on 16 November 2012. Our CEO got this recognition during CNBC’s 11th edition of Asia Business Leaders Awards (ABLA) function held at Bangkok, Thailand. Click here to know more.
IV. CEO & MD, N Chandra, won ‘Pathfinder CEO’ of 2012 by National HRD Network (NHRDN)
TCS CEO & MD, N. Chandra was presented with the ‘Pathfinder CEO’ award by National HRD Network (NHRDN) during its 16th National Conference held from 29 November to 1 December 2012 at Hyderabad in India. NHRDN recognises individuals and organisations who have made noteworthy contributions in the area of Human Resource Development in the Corporate sector, Academic sphere and broader Business and Social arena.
V. TCS received the Forbes Asia 'Fabulous 50' Award
TCS was presented the Forbes Asia 'Fabulous 50' Award in a award ceremony held in Macau, China on 4 December 2012. This came about after Forbes Asia, a leading pan-Asia business magazine, listed TCS in its prestigious and influential annual 'Asia's Fab 50' list of the most compelling companies in Asia, earlier this year.
VI.TCS Ex-CFO, S Mahalingam, won ‘CFO of the Year’ award at CFO Innovation Asia Awards on 28 November 2012
TCS Finance swept the two main categories at the CFO Innovation Asia Awards on 28 November 2012 in Singapore, with TCS CFO S Mahalingam winning the marquee 'CFO of the Year' award, and TCS Finance team recognised as 'Finance Team of the Year'. The event was attended by over 120 Asia-based CFOs and top-tier financial executives and featured over 15 award categories pitting the biggest names in the finance arena, including banks (HSBC, Citi), accountancy firms (KPMG, PwC, Deloitte) and service providers (Accenture, Infosys). Click here to know more.
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References
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