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CPSC330 Digital Logic Design

Peiyi ZhaoChapman University

2009

Design Inverter (NOT logic)using Layout Editor: Magic

• CMOS transistor layers and model

• Basic layout

• Magic layout tool tutorial(with NOT gate as an example)

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• MOS transistor is a sandwich of several layers of conducting and insulation materials.

Red : gate Green: n+ type Brown: p+ type

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Red : gate Green: n type(negative

type)

n typen type

drain

source

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Red : gate Green: n type(negative

type)

n typen type

drain

source

NMOS Transistor is ON when applying positive voltage on its gate, attracting negative charges to accumulate between two n type area

Transistor is OFF when applying ‘O’ voltage on its gate

+5 v

0 v

Gate+5 v

NMOS 门 gate 上加 电源电压后，吸引了负电荷堆积在source ,drain 两极间，使该 两极间产生通道， NMOS 就导通了

• NMOS: input on gate= 1, NMOS on

• = 0, NMOS off

• PMOS : opposite to NMOS (note:a small circle o on symbol)

input on gate =0, PMOS on

=1, PMOS off

Inverter 反相器

input

PMOS

Input=1,NMOS on, PMOS off

output =0

Ground

Supply voltage

Output has a path to ground through NMOS

output

PMOS

Input=0,NMOS on, PMOS off

output =1

Output has a path to Supply voltage through PMOS

input output

0 1

1 0

Truth table:it shows the design is inverter

NAND 与非门

Ground

PMOS

Supply voltage

Input 1

Input 2

Input 1 Input 2

NMOS

PMOS

Input 1

Input 2

If input1=1, input2=1, both NMOS are ON, output has path to ground. So output=0

output

output

If input1=0, or

input2=0, both NMOS are OFF, but one PMOS will be ON. output has path to Supply voltage,so output=1

NMOS

PMOS

Input 2

Ground

Supply Voltage

0 0 1

0 1 1

1 0 1

1 1 0 Out=In1 NAND In2

Input1 Input2 Output

Truth table: shows it is exactly NAND logic

Dual design: 举例 :NOR 与或门 :NMOS 并联时 ,PMOS 对偶的部分 串联 DDual Design: PMOS in serial, NMOS in Parallel;

Ground

PMOS

Supply voltage

Input 1

Input 2

Input 1Input 2

output

If input1=0, or

input2=0, both NMOS are OFF, but one PMOS will be ON. output has path to Supply voltage,so output=1

NMOS

PMOSSupply Voltage

0 0 1

0 1 0

1 0 0

1 1 0 Out=In1 NOR In2

Input1 Input2 Output

Truth table: shows it is exactly NOR logic

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Side View Top view , turn clockwise 90

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Side View Top view , turn clockwise 90

• Stick Diagram:• Red: poly• Green:Diffusion(n type or p-type):• Blue:metal

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Basic Unix commands• cd my_directory (go to the directory)• ls my_directory (list)• cp (copy)• pwd : present working directory• mv my_file my_another_directory (move file)• mv old_file_name new_file_name (rename)• rm file_name (remove file)• find . –name “myExample.txt” –print• grep text files• mkdir myDirectory (create new directory)• passwd: change passwd• chmod 711 ~: change permission• Tip:do not use ftp to transfer files, since ftp does not have encryption of your

password; use ssh instead. • Good link:

http://userwww.sfsu.edu/~necrc/files/server%20connection%20tutorials/Basic_Unix_Commands.pdf by Hamid Mahmoodi

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Magic layout tool

• Developed by UC Berkeley

• Being used in Stanford, MIT, USC,etc

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In command line, typemkdir tutorialcd tutorial

Type in command line:magic tutorialOne graphic window will pop out(Note: you have one text window, one graphic window respectively now, your cursor should point to the graphic window always). Next time, if you already have tutorial.mag file, do not include .mag in above command;

In text window, type colon ”:” to invoke command::grid 1

If you type colon, you must enter command and carriage before doing anything else.

Shape of cursor: when you press SPACE, 4 shapes toggles: cross, arrow, square, hand. Currently we are using cross shape for position rectangular area for a layer. If you unintentionally press the SPAC, and the cursor shape is not cross, then press SPACE as many times as needed till the cross appears.

Left click of the mouse button on the window to determine the lower left corner of the layer area, move cursor and right click for the upper right corner. A box will appear.

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1. First paint p+ type (brown color), with width 4 units:paint pdiff

2. Paint gate which is polysilicon (red), with width: 2, on top of p+ type

:paint poly

3.Similarly paint n+ type(green)

:paint ndiff

Width:4 units

• Connect the gates(red)

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Paint : metal (blue color)

:paint m1

Paint : metal to p+ (pdiffution ) contact:paint pdc

Paint :metal to n+ (ndiffution ) contact:paint ndc

If white dots appear, those are errors. Box white dot area, type :drc why (design rule check)You will get error message

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• Add more metal(for supply voltage) :paint m1

Tip: frequently save your design, type:save

• Paint gate(poly) to metal contact(purple):paint polycontact

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Inverter Layout: Final View

• Paint nwell (diagonal lines):paint nw

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• Inverter Layout: another way : poly is vertical• Paint gate(poly) to metal contact(purple)

:paint polycontact

N+: paint ndiff or :paint green

P+: paint pdiff or :paint brown

Gate, poly: paint poly or red

p-contact: paint pdcontact

n-contact :paint ndiff

metal: paint m1

Psubstrate-contact :paint pwc

Nwell-contact: paint nwc

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• Label names: move cursor to point of the layer you want to add label,left click then right click at the same position, then type:label myLabel

for example,

• :label in:label out:label Vdd:label gnd

out

in

NAND: what is missing

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Once you finish your design, type:save

You will find a file named tutorial.mag in your directory.To open this magic file, type:magic tutorial (not :magic tutorial.mag)

Finally type cd .. will bring you up one level to your home directory. Suppose you will

design a NAND, first create directory by type mkdir NAND cd NAND magic NAND it will open a new magic layout window.

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Other commands:• select area short key: a• undo short key: u• delete• view short key:v, V• zoom short key:z,Z• 5: the key on the right panel on the key board, center the area your box positioned.

Other key nearby with arrow can be used to move the layout.• save• quit (to exit)• drc whyTips• After you are familiar with the layers, you can use shortcut keys and colors, like : pai

red is the same as : paint poly• You should point your cursor to the layout window when you type your command in

the text window.• . dot is to repeat the previous command (compare in Unix: use up, down, left, right

arrow )• moving: select an area, type ‘a’, move that part using 4 arrows(up, down, left, right)

on the right most part on the key board. • copy: select an area, move your cure to another point, press ‘c’ in your keyboard• paint: draw a box, if you want to paint metal, move your cursor to metal that in already

in your layout, and press middle button

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• Links: • Magic brief overview

http://vlsi.ece.iit.edu/scells/ece429/MAGIC1x.html

• Step by Step layout example of an inverter:http://www.ece.umd.edu/~newcomb/vlsi/magic_tut/Magic_x3.doc

• Magic inverter tutorial http://vlsi.ece.iit.edu/scells/magic/