cadence online documentation tutorial

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www-scf.usc.edu/~ee577/cadence_tutorial4.html 1

Cadence Tutorial 4: Schematic of a parameterized Inverter

1. Open schematic window.

File->New->Cellview

In Create New File window,

Library Name : Mylib

Cell Name : inverter

View Name : schematic

Tool : Composer-Schematic

2. Place nmos transistor.

sch:Add->Component (or "i")

Add Component:click Browse

In Library Browser window,

Library : tsmc25LibCell : nfet3

View : symbol


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1. Place pmos, vdd, and gnd.

- Repeat above procedure for pfet3, vdd, and gnd placement. All components can be found at the

same library (tsmc25Lib or basic).


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2. Connect each component using wires.

Place mouse pointer on one of the node you want to connect

sch:Add->Wire(narrow) (or "w")

Click "mouse L", drag to other node to connect, and click "mouse L" to finish.

- Repeat above procedure to finish wiring.

- To make wire open node at one end (like input and output of inverter), double-click "mouse L"


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3. Place pins.

sch:Add->Pin (or "p")

In Add Pin window,

Pin Names : A X

Direction : input

Move mouse to place A pin at input of inverter, then click "mouse L".

In Add Pin window, change direction to output.

Place X pin at output of inverter.


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4. Add pmos parameters. (W/L)

Click pfet3

sch:Edit->Properties->Objects (or "q")

In Edit Object Properties window,

Width : pPar("pw")

Length : pPar("pl")

Click OK or Apply

Repeat for nfet3 with width pPar("nw") and length pPar("nl").

Comment:pPar means its parameter value is inherited from parent schematic. pPar(pw) can be

interpreted as set the width to the parameter pw of its parent schematic. In this example, there arefour parameters (pw, pl, nw, nl) which can be individually controlled from the schematic that calls

the symbol of this schematic.

Please refer to chapter8 Editing Properties -> Passing Parameterssection in Cadence Virtuoso

Schematic Composer User guide for more details.


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Check and Save

sch:File->Check and Save

Inverter Symbol Create

1. Open symbol window.

icds:File->New->Cellview

In Create New File window,

Library Name : MyLib

Cell Name : inverter

View Name : symbol

Tool : Composer-Symbol

1. Draw outline for inverter symbol.

Click line icon on left toolbox of symbol window and draw outline of inverter.


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3. Finish outline by adding circle.

sym:Add->Shape->Circle

Click "mouse L" on the center of circle, drag and click "mouse L" again.


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4. Place pins.

sym:Add->Pin (or "p")

In Add Pin window,

Pin Names : A X

Direction : input

Type : square

Move mouse to place A pin at input of inverter, then click "mouse L".

In Add Pin window, change direction to output.

Place X pin at output of inverter.


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5. Add labels.

sym:Add->Label

In Add Label window,

Label : [@instanceName]

Place label.


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6. Add NLPLabel for parameters.

Add->Label

Label: [@pw:%:][@pl:/%:]

Label Type:NLPLabel

Label: [@nw:%:][@nl:/%:]

Label Type:NLPLabel

Comment: Putting NLPLabel for symbol will help you recognize the property of the instance in theschematic that uses this symbol.


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7. Add CDF Parameters for the cellview.Tools->CDF->Edit

CDF Type: Base

Library Name: MyLib

Cell Name: inverter

Component Parameters: Click Add

paramType: float

storeDefault: yes

name: nw(pw,nl,pl)

prompt: nw(pw,nl,pl)

defValue: 0.5u (or value of your choice, 0.24u for length)

Click Apply or OK


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For more help please refer to Virtuoso Schematic Composer user guide using CDSDOC.

In case of any bug or comment please email to [email protected] or [email protected]

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