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Internship Report

FOREWORDeSilicon is a fabless semiconductor company founded in 2000 and based Sunnyvale, California. eSilicon designs and manufactures digital CMOS ASICS. eSilicon is considered a pioneer of the fabless ASIC model and is the worlds largest fabless ASIC supplier. eSilicons headquarters is in Sunnyvale, California. eSilicon has offices in Allentown, PA, New Providence, NJ, Bucharest, Romania, Yokihama, Japan and VietNam(on design center in Ho Chi Minh city and another in Da Nang city) eSilicon provides physical design, design for test insertion, package design, product qualification, IP licensing, and manifacturing services for difital CMOS ASICs. eSilicon has announced products in 25um,18um, 13um, 90nm, 65nm,40nm and 28um process technologies. Customer ASICs have been announced in a wide range of appplications including digital cameras, portable multimedia players, inkjet printers, networking and high performance computing. In February 2008 it was announced that eSilicom had licensed Avago Techologies high performance 90nm and 65nm SerDes technology for use in eSilicons customers designs. For the purpose of enabling studens to have access to the real working environment. Electronics-Telecommunications Department, Da Nang University of Technologies And Union Corporation eSilicon Vietnam have created favorable conditions for us to practice at company. I would send the most sincere gratitude to company, whom enthusiastically helped us during prative.

Reporter : Vo Thanh Liem

Supporter : Nguyen Ba Mich

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Internship Report

CONTENTS FOREWORD....1 CONTENTS..2 CHAPTER1 UNIX OVERVIEW.3 CHAPTER2 SCHEMATIC AND CIRCUIT SIMULATION6 2.1 Schematic....6 2.2 Circuit Simulation...8 2.3 Inverter Simulation.....9 2.3.1 Inverter Introduction....9 2.3.2 Inverter Simulation..9 CHAPTER3 MINI PROJECTS : 6T CMOS SRAM CELL..13 3.1 SRAM overview...13 3.2 6T SRAM CELL Simulation....17

Reporter : Vo Thanh Liem

Supporter : Nguyen Ba Mich

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Internship Report

CHAPTER1

UNIX OVERVIEW

UNIX OPERATING SYSTEM 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 a graphical user interface(GUI) similar to Microsoft Windows which provides an easy to use enviroment. Howeverm knowledge of Unix is required for operations which arent convered by a graphical, or for when there is no windows interface available, for example, in a telnet session. 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 file myfile). The sghell searches the filestore for the file containing the program rm, and then request the kernel, through system calls, to execute the program rm on myfil. 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.

Reporter : Vo Thanh Liem

Supporter : Nguyen Ba Mich

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Internship Report

The shell The shell acts as an interface between the user and ther 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(CLC). It interprets 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 custumise his/her own shell, and users can use different shell on the same machine. Staff and students in the school has certain features to help the user iputting commands. Filename Completion By typing part of the name of a command, filename or diractory 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 istory for a lisy of previous commands. Several shell available with Linux including: Bourne, C, Korn shell etc. But we consider only C-shell.

Reporter : Vo Thanh Liem

Supporter : Nguyen Ba Mich

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Internship Report

How to use Shell To use shell (You start to use your shell as soon as you log into your system) you have to simply type commands. What is Shell Script ? Normally shells are interactive. It means shell accept command from you (via keyboard) and execute them. But if you use command one by one (sequence of 'n' number of commands) , the you can store this sequence of command to text file and tell the shell to execute this text file instead of entering the commands. This is know as shell script. Shell script defined as: "Shell Script is series of command written in plain text file. Shell script is just like batch file is MS-DOS but have more power than the MS-DOS batch file." Why to Write Shell Script ?

Shell script can take input from user, file and output them on screen. Useful to create our own commands. Save lots of time. To automate some task of day today life. System Administration part can be also automated.

Reporter : Vo Thanh Liem

Supporter : Nguyen Ba Mich

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Internship Report

CHAPTER 2

SCHEMATIC & CIRCUIT SIMULATION

2.1 SCHEMATIC To complete a schematic we have to go through these steps : Start Custom Designer

Creat A Design Database

Create A Schematic

Topology Overview

Create Instance

Add Pins

Add Wires

Create Wire Names

Check And Save The

Reporter : Vo Thanh Liem

Supporter : Nguyen Ba Mich

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Step 1 : To Run Custom Design(CD) sofware, we have to create C-script, which includes path of CD run-file, path of license-key file, path of library definition files(library difination file indicate to path of library folder), and some other necessary information. Step 2 : Creating a design folder. Step 3 : Creating schematic cells in design folder. Step 4 : Overviewing topology. Step 5: Adding instances and changing accordingly the parameters of instances, then arranging reasonable in order and wiring the pins of instances. Step 6 : Adding input and output pins Step 7 : Creating wire names Step 8 : Check and Save.

Reporter : Vo Thanh Liem

Supporter : Nguyen Ba Mich

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2.2 CIRCUIT SIMULATION To simulating a circiuit, we must first run Simulation Sofware. To running Simulation Sofware we have to create a C-script, which includes path of run-file, path of license-key file, path of input and ouput file.

+ Input file : including paths of 4 files : options file(some options for simulation : file.option), netlist file(the wired of instances : file.spi), setup file(initial circuit paramaters and input waveforms : file.setup ) and model file(parameter of instances). + Output file : containing simulation results.

Reporter : Vo Thanh Liem

Supporter : Nguyen Ba Mich

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2.3 INVERTER SIMULATION 2.3.1 Inverter Inverter is most basic gate in CMOS technology. It includes pull-up network with PMOS and pull-down network with NMOS. Ouput signal be inverted compared with input signal. 2.3.2 Inverter Simulation a\ Vout follow on Vin

Reporter : Vo Thanh Liem

Supporter : Nguyen Ba Mich

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0-2ns : Vin=0, Vout=Vdd : P1 turn on, ouput be pulled up to Vdd and N0 turn off, holding high impedance state. 2-2,02ns : Vin increase from 0V to Vdd to cause P1 impadence ascending and impadence N0 descending. At the moment, from source to mass seeing Rp1 and Rn0 as two serial resistors, so current follow from source to mass drop on ouput a voltage : Vout=Vdd.Rn0/(Rn0+Rp1) So when Vin descending then Vout ascending until Vin is 0 then Vout is Vdd. There is an inportant point of inverter should be noted that delay Td(the time distance between 50% amplitude of input and output), suppose that Vout is floating, if Vout> Rn15,Rn16 so C5,C13 discharged much faster, causing Rn17 rapid increase, as do C6,C14 discharged slowly(N15 still turn on). Until rbl recuded upper Vtrip of NOR_out gate then this gate would be opposite state. 3 Ton b qu trnh ghi v c

Reporter : Vo Thanh Liem

Supporter : Nguyen Ba Mich