dost-asti electric manual

7/26/2019 DOST-ASTI Electric Manual

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Electric

VLSI DesignSystem

Training Manual

(Version 6.03)

Advanced Science and Technology Institute

Department of Science and Technology

ASTI-VCTI OpenLab Training Series

Introduction to Full-Custom Digital IC Design Flow


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Advanced Science and Technology InstituteDepartment of Science and Technology

ASTI-VCTI OpenLab Training SeriesIntroduction to Full-Custom Digital IC Design Flow

2

Loading Electric

Load Electric by either clicking the Electric icon on the desktop or by clicking on

Start Programs Electric.

The Electric Display

Shown below is a typical Electric display with some of its essential features.

The editing window or design window is the largest window that initially says Nofacet in this window (this indicates that no circuit is being displayed in that window).

The messages windowis a text window that is typically found at the bottom of the

screen. This is used for all textual communication.

Thepulldown menucontains a list of command options.

The components menushows a list of nodes or components (in black outline) and

arcs or wires (in red outline) that can be used in the design. The selected arc is highlightedwith a bolder red outline.

The status areaprovides useful information about the design state.

Editing Window

Messages Window

Pulldown Menu

Status Area

Components Menu


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SCHEMATIC

Setting the Schematic Technology

1. Click on Technology Change Current Technologyfrom the pulldown menu.2. Select schematic, analogas the technology (you will have to scroll down to find it).3. Click OK. Notice that the symbols in the components menu will change to a

schematic set.

4. Click on the 4 Port box in the components menu. This will convert all thetransistors in the components menu to 4-port transistors.

Changing the Lambda Size

1. Click on Technology Change Units.

2. Change Lambda Sizeto 2000.

3. Change Display Unitsto Microns.4. Change Internal Unitsto Half-Millimicrons.

5. Click OK.

Creating a New Library

1. Click on File New Libraryon the pulldown menu.

2. Type the library name that you want to create.

3. Click OK.4. To save the new library, click on File Save Libraryon the pulldown menu.

5. On the Library File Creationwindow, browse through the file folders and select the

folder where you want to save the library.

6. Click OK. A message confirming that the new library has been saved will bedisplayed in the message window.

Creating a New Schematic Facet

1. Click on Facets Edit Facet.

2. Select the appropriate library.

3. Click New Facet.4. Type the facet name that you want to create. Set the facet view to schematic.

5. Click OK.

Adding Components

1. Select the desired device in the components menu by using the left mouse button. Awhite outline will appear around the chosen component.

2. Click on the design window to drop the component.

Selecting Components and Ports1. To select a component, left click on the node or component in the

design window. A box that highlights the component appears, whichindicates that it has been selected.

In the second and third figure on the right, DC voltage sources are

shown with highlights indicating that these components were selected.2. Ports are the connection sites on nodes where the wires connect. A

single node could have several ports. To select a port, click inside thefigure of the node near the location of the desired port.

The second and third figures on the right are voltage sources with thepositive and negative terminals selected, respectively.


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Changing Components Properties

1. Highlight the device property labelby clicking it. A white Xmark should appear onthis label.

2. Double click the property label to access the device Informationwindow.

3. Modify the properties that you want to change.

4. Click OK.For the voltage sources in the previous page, the deviceproperty labelis DC.

Adding Export Pins

1. Select the node in the components

menu.2. Click on the design window to drop the export

pin.

3. Type the export name and indicate theappropriate export characteristic. Table 1lists

the most commonly used export pins and theircorresponding export characteristics.

4. Click OK.

Adding Wires1. In the components menu, check if the wire arc(blue line) is highlighted (with a bold

red outline). If it is not highlighted, click on the wire arc to select it.2. Select the wire starting point by left clicking the component near the desired port.

Make sure that the desired port is highlighted, as discussed in Selecting Components

and Ports, before proceeding to the next step.3. To create the wire, right click on another device port (to connect two device ports) or

anywhere on the design window (to create a wire segment). Once a wire has beencreated, the other end is highlighted.

Adding Voltage/Current Sources1. In the components menu, click the Spicenode to access the Spice list.

2. Choose Voltage/Current Sourcefrom the Spice list.3. Click on the design window to drop the voltage/current source.

4. Type the appropriate SPICE cardparameters in the SPICE Card window. Table 2isa list of SPICE card formats for the different types of sources.

5. Click OK.

Adding Voltage/Current Meters

1. In the components menu, click the Spicenode to access the Spice list.2. Choose Voltage/Current Meterfrom the Spice list.

3. Click on the design window to drop the voltage/current meter.4. To plot the voltage across a device, connect the voltage meter in parallel to that

device. To plot the current through a device connect the current meterin seriestothat device.

Choosing the Circuit Analysis1. In the components menu, click the Spicenode to access the Spice list.

2. Three options (transient, DCand AC) are available for the circuit analysis. Choosethe appropriate analysis from the Spice list.

3. Click on the design window to drop the chosen analysis.

Table 1

Export PinExport

Characteristic

Vdd Power

Gnd Ground

Input Input

Output Output


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4. Type the appropriate SPICE cardparameters in the SPICE Card window. Table 3is

a list of SPICE card formats for the different analyses.5. Click OK.

Table 2

Source Type Syntax ParametersDC DC Value Valuethe value of the source

Pulse PULSE(V1 V2 TD Tr Tf PW Pd)

V1 initial value

V2 peak value

TD initial delay time

Tr rise time

Tf fall time

PW pulse width

Pd period

Piecewise

linear (PWL)PWL(T1 V1 T2 V2 T3 V3)

(TiVi) the value Viof the source at

time Ti

Sinusoid SIN(VO VA FREQ TD THETA PHASE)

VO offset value

VA amplitudeFREQ frequency in Hz

TD delay in seconds

THETA damping factor per second

PHASE phase in degrees

Table 3

Analysis Syntax Parameters

Transient TSTEP TSTOP

TSTEP printing increment

TSTOP final time

TSTART starting time (if omitted,TSTART is assumed to be zero)

TMAX maximum step size

UIC (Use Initial Condition) instructs

SPICE to use the specified initial

condition instead of the quiescent

operating point before beginning

the transient analysis.

DC START STOP STEPSTART starting value

STOP ending value

STEP size of the incrementAC

With linear

frequencyvariation LIN NP FSTART FSTOP

NP number of points

FSTART start frequency in HzFSTOP stop frequency in Hz

With decade

variationDEC ND FSTART FSTOP

ND number of frequency points

per decade

FSTART start frequency in Hz

FSTOP stop frequency in Hz

With octave

variationOCT NO FSTART FSTOP

NO - number of frequency points

per octave

FSTART start frequency in Hz

FSTOP stop frequency in Hz


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6

Saving the Schematic

To save the schematic design that you created, click on File Save All Librariesfromthe pulldown menu. (Using the shortcut control key Ctrl-Swill also save the circuit.) A

message confirming that all facets of the library has been saved will be displayed in themessage window.

Creating an Icon for the Schematic1. To create the icon facet of a schematic, open first its schematic facet. An icon is a

symbol facet associated to the schematic facet. Make sure that you have created allthe relevant exports before creating the icon.

2. To configure the appearance of the icon,

click on View Icon Options.

a. Make sure that the options havethe settings as listed in Table 4.

b. Check the Draw leadsoption.c. Check the Draw bodyoption.

d. Click OK.

3. Click on View Make Icon from the

pulldown menu to create the icon facet.

A new design window will appearcontaining the icon.

4. Edit the icon facet if you want to make further changes on its appearance.

Creating a Schematic SPICE Netlist

1. Click on Tools Simulation Interface SPICE Options.

a. Set the File format to SPICE3 and the SPICE levelto 3.b. Check the Use Node Names option.

c. Click on Use Header Cards From File. In the SPICE Model File Selectionwindow set the file type to All Files (*.*).

d. Browse through the folder list to locate the model file

(\\Electric\models\BSIM3v31.txt). Select the model file.e. Click OK.

2. Before creating the SPICE netlist, make sure that all connections are checked. RefertoChecking for Connectivityon the Tipssection of this manual.

3. Click on Tools Simulation Interface Write SPICE Deck from the pulldown

menu to create a SPICE netlistof your schematic design.

4. Add a .cirextension to the file name.5. Click Save.

Table 4

Inputs on Left side

Outputs on Right side

Bidir. on Top side

Power on Top side

Ground on Bottom side

Clock on Left side

Export location Lead endExport style Outward

Export technology Schematic


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LAYOUT

Setting the Layout Technology

1. Click on Technology Change Current Technologyfrom the pulldown menu.2. Select mocmossubas the technology (you will have to scroll down to find it).3. Click OK. The symbols in the schematic menu will change to a mocmos subset.

Changing the Lambda Size

1. Click on Technology Change Units.

2. Change Lambda Sizeto 350.

3. Change Display Unitsto Microns.4. Change Internal Unitsto Half-Millimicrons.

5. Click OK.

Creating a New Layout Facet

1. Click on Facets Edit Facet.

2. Select the appropriate library.3. Click New Facet.

4. Type the facet name that you want to create. Set the facet view to layout.5. Click OK.

Adding Nodes1. Select a node from the components menu by using the left mouse button.

2. Click on the design window.Note:Nodes in the mocmossub components menu are the ones in blue outlines.

Adding Arcs

1. Select an arc in the components menu.2. Choose the arc starting point by left clicking the node near the desired port. Make

sure that the desired port is highlighted before proceeding to the next step.

3. To create the arc, right click on another node port (to connect two node ports) oranywhere on the design window (to create an arc segment). Once an arc has been

created, the other end is highlighted.Note:Arcs in the mocmossub components menu are the ones in red outlines.

Adding Export Pins

1. Select the node or arc to be exported.

2. Click on Export Create Export.

3. Type the export name and indicate the appropriate export characteristic.

Checking the Layout for Design Rule Errors

Before proceeding to the simulation, check for any layout violations by running a DesignRule Check (DRC). Design rules are the set of rules that must be followed when a given

design is laid out. To run a DRC, click on Tools DRC Hierarchical Check.

Saving the Layout

To save the layout that you created click on File Save All Libraries from thepulldown menu. (Using the shortcut control key Ctrl-S will also save the layout.) A

message confirming that all facets of the library has been saved will be displayed in the

message window.


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Creating a SPICE Netlist Using the Layout Instance

1. Create a new schematic facet by following the instructions in the Schematicsectionof this manual.

2. Click on Edit New Facet Instance. Click the name of the layout that you wantto instantiate.

3. Click OKand click on the design window. An instance box of the circuit layout nowappears on the design window.

4. Click on Export Re-Export Everything.5. Add necessary components for simulation such as voltage/current sources, ground,

voltage/current meters and load capacitances.

6. Save the circuit.7. Change the current technology to mocmossub. Notice that the symbols in the

components menu will change from a schematic set to a layout set.

8. Click on Tools Simulation Interface SPICE Options.

a. Set the File format to SPICE3 and the SPICE levelto 3.b. Check the Use Node Names option.

c. Check the Use Parasitics option.d. Click on Use Header Cards From File. In the SPICE Model File Selection

window set the file type to All Files (*.*).

e. Browse through the folder list to locate the model file(\\Electric\models\BSIM3v31.txt). Select the model file.

f. Click OK.9. Before creating the SPICE netlist, make sure that all connections are checked. Refer

toTransistor Layouton the Tipssection of this manual.

10. Click on Tools Simulation Interface Write SPICE Deck from the pulldown

menu to create a SPICE netlistof your circuit design.11. Add a .cirextension to the file name.

12. Click Save.

Determining the Area of the Layout

1. Click on Info Measure Distancefrom the pulldown menu.2. Press Xon the keyboard. This key tells Electric that you are ready to specify the

starting point of your measurement.3. Left click on the starting point of your measurement.

4. Left click on the end point of your measurement. A line appears and the value of thelength is shown.

5. Press the Enterkey when done.


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SIMULATION

Simulating the Circuit Behavior Using WinSpice

1. Run WinSpice by clicking on Start Programs WinSpice.2. Open the *.cir file in WinSpice.

3. Wait until WinSpice starts displaying the simulation data. Press Esc to skip the

viewing of data points. WinSpice will automatically plot in a single window allvoltages and currents that were specified in the schematic.

Plotting Waveforms in Separate WindowsThere are 2 ways to plot the parameters in separate windows.

Through the cir file:1. Open the *.cir file using Notepad or any other text editor program.

2. Add the following line for each parameter to be plotted in a separate window:

.PRINT

3. Run the simulation in WinSpice.

Example:Plotting several parameters in one window,

.PRINT TRAN V(Va) V(Vb) V(Vout)

The above picture shows the transient response of Va, Vb and Vout superimposed inone plot. To plot each parameter in separate windows, delete the above code andrewrite it as:

.PRINT TRAN V(Va)

.PRINT TRAN V(Vb)

.PRINT TRAN V(Vout)

Through the WinSpice command prompt:

If the simulation has been run already, simply type the following on the WinSpice command

prompt:plot

Example: Winspice 1 -> plot v(va)Winspice 2 -> plot v(vb)Winspice 3 -> plot v(vout)


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SHORTCUT CONTROL KEYS

Open Library Ctrl-O

Save All Libraries Ctrl-S

Quit Ctrl-Q

Cut Ctrl-X

Copy Ctrl-C

Paste Ctrl-V

Duplicate Ctrl-M

Undo Ctrl-Z

Redo Ctrl-R

Rotate 90 Degrees Counterclockwise Ctrl-J

Select All Ctrl-AEdit Facet Ctrl-N

Down Hierarchy Ctrl-D

Up Hierarchy Ctrl-U

Look Inside Highlighted Ctrl-P

Create Export Ctrl-E

Fill Window Ctrl-9

Zoom Out Ctrl-0

Zoom In Ctrl-7

Fit to Screen Ctrl-9

Focus on Highlighted Ctrl-F

Left Ctrl-4Right Ctrl-6

Up Ctrl-8

Down Ctrl-2

Toggle Grid Ctrl-G

Delete Window Ctrl-W

Get Info Ctrl-I


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ELECTRIC AND WINSPICE ERROR/ WARNING MESSAGES

Listed here are some of the most common errors encountered and their corresponding

solutions.

Electric Warning Messages

Warning: there may be inconsistent ground networks in Warning: there may be inconsistent power networks in Warning: top of source [nodex]/DC 3.3 in facet not connected toan export

This means that the ground and power in the circuit is not connected to the DC source.Refer to Checking forCconnectivityin the Tipssection of this manual.

WinSpice Error Messages

Illegal Characters in the SPICE Netlist

Error in x.cir on line x : _nodex xxx x=> unknown device type - error

To remove this type of error, follow these steps.1. Open the *.cir file using Notepad or any other text editor program.

2. Scroll down and look for the illegal character . Substitute all occurrences of thischaracter with the letter v.

3. Save the text file.

Example:

** Sources and special nodes:node11 Vout_1 Vout DC 0Vnode9 Vout_1 0 sin(1.65 1m 1k 0 0 0)Inode6 VDD Ibias DC 100uVnode2 VDD 0 DC 3.3.PRINT TRAN I( node11) V(Vout_1).TRAN 10u 10m 10u.END

Corrected Example:

Notice that all occurrences of are now substituted with v.

** Sources and special nodes:vnode11 Vout_1 Vout DC 0Vnode9 Vout_1 0 sin(1.65 1m 1k 0 0 0)Inode6 VDD Ibias DC 100uVnode2 VDD 0 DC 3.3.PRINT TRAN I(vnode11) V(Vout_1).TRAN 10u 10m 10u.END

Note: Text characters in a SPICE netlist are not case-sensitive.


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Unconnected Nodes

Error in x.cir on line x : mnodex Vout Vin 0 * N L=0.35U W=0.80UError in x.cir on line x : mnodex Vdd Vin Vout * P L=0.35U W=3.20UOnly level 9 B3S0I can have 5 nodes

Note:*in the beginning of a line denotes it is a comment in the program and is therefore not an error, while an *within a command denotes a missing node in the program


2. Scroll down and look for the line mentioned in the error message.

Example: Mnode5 Vout Vin 0 * N L=0.35U W=0.80UMnode6 Vdd Vin Vout * P L=0.35U W=3.20U

3. Check the schematic for unconnected nodes in the transistors. For this example, the

bulk nodes are unconnected. Connect the bulk correspondingly (to ground for NMOSand to Vdd for PMOS).

4. Save the schematic and recreate the SPICE netlist. Check if the line is correctlymodified by opening the *.cir file again.

Corrected Example: Mnode5 Vout Vin 0 0N L=0.35U W=0.80UMnode6 Vdd Vin Vout VddP L=0.35U W=3.20U

Missing Model Files

Unable to find definition of model 1 default assumedError: no unlabeled parameter permitted on mosfet

Error: unresolved model or device references: -p n


2. Check if the model files for NMOS and PMOS are at the top most part of the file.

Example: .model P PMOS++

.model N NMOS++

3. If the model files are not found, go to the schematic window.

4. Check the spice options by clicking on Tools -> Simulation Interface -> SPICEOptions.

5. Make sure that all the settings are as specified in the Schematic section of thismanual.

6. Re-create the SPICE netlist by clicking on Tools -> Simulation Interface -> WriteSPICE Deck.

7. The model file should already be included in the *.cir file.


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TIPS

Checking for Connectivity

Click on a component. All connections to the component should appear highlighted.

Example:

Notice that all the nodes connected to ground are highlighted. An example of an

unconnected wire is shown below:

The ground in black circle is not connected to the rest of the nodes connected to ground. Ifthis is the case, do the following:

1. Save the library (Ctrl-S).2. Open the same library without closing the current facet.

3. Check for connectivity. The nodes concerned should now all be highlighted.


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Transistor Layout

1. Overlapping two nodes does not automatically connect them. This will only generate

spacing errors. Make sure to connect them first using an arc and then move them closer

as in the example below:

a. Unconnected b. Connected c. Compress further

2. Try to move the node closer one step at a time while checking the message windowto see if a DRC error is generated. Or you can perform the DRC independently as

specified in the Layoutsection of this manual.3. Checking their connectivity is the same as with the schematic. Clicking a node should

highlight all that is connected to it as in the figures below.

Connected Unconnected

All nodes connected are highlighted

4. If nodes are well connected, and there are still spacing errors, double click on the arc

connecting the nodes with the spacing error.


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5. Uncheck ends extend (This option sizes the node / arc in proportion to the node

width).6. Another cause of spacing errors is multiple components that are overlapping. One can

easily identify this by moving the component concerned and checking if there is an

extra component under it as in the example below.

Two coinciding nodes Extra component under the node

In this case, the extra component is not connected to the other nodes and so it

generates the other spacing errors. Simply delete the extra component and run aDRC again.

7. If there is still a spacing error, then the two nodes must be really too close. One ofthe nodes should therefore be moved until the error disappears.


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DESIGN RULES FOR MOCMOSSUB TECHNOLOGY

Arc widths (minimum sizes):

metal1: 3metal2: 3metal3: 5metal3: 3metal4: 6poly1: 2poly2: 3p/n active (active&select&well):active: 3, select extends by 2, well extends by 6

active: 3

Pin/Node sizes (minimum sizes):

metal1: 3

metal2: 3metal3: 5metal3: 3metal4: 6poly1: 2poly2: 3active: 3select: 2well: 12

Special nodes:

p/n active-to-metal1 contact:cuts 2x2, separated 3metal1 extends around cut by 1 (4x4)

active extends around cut by 1.5 (5x5)select extends around active by 2 (8x8)well extends around active by 6 (17x17)

poly1-to-metal1 contact:cuts 2x2, separated 3metal1 extends around cut by 1 (4x4)poly1 extends around cut by 1.5 (5x5)

poly2-to-metal1 contact:cuts 2x2 , separated 3metal1 extends around cut by 1 (4x4)poly2 size: 3 (3x3)

poly1-to-poly2 (capacitor) contact:cuts 2x2 [5.1], separated 3

poly2 size: 3 (3x3)poly1 extends around poly2 by 2 (7x7)Transistors:active is 3 wide and sticks out by 3 (3x8)poly1 is 2 wide and sticks out by 2 (7x2)transistor area is 3x2select surrounds active by 2 (7x12)well surrounds active by 6 (15x20)

Via1:cuts 2x2, separated 3


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metal1 extends around cut by 1 (4x4)metal2 extends around cut by 1 (4x4)

Via2:cuts 2x2, separated 3metal2 extends around cut by 1 (4x4)

metal3 extends around cut by: 2 (6x6) (if 3-metal process)metal3 extends around cut by: 1 (4x4) (if 4-metal process)Via3:cuts 2x2, separated 4metal3 extends around cut by: 1 (4x4)metal4 extends around cut by: 2 (6x6)

Substrate/well contact:select extends around active by 2well extends around active by 6

DRC:

metal1-to-metal1: 3metal2-to-metal2: 4metal3-to-metal3: 3

metal4-to-metal4: 6poly1-to-poly1: 3poly1-to-active: 1poly2-to-poly2: 3poly2-to-active: 1poly2-to-polyCut: 3active-to-active: 3select-to-trans: 3polyCut/actCut-to-polyCut/actCut: 3polyCut/actCut-to-via1: 2polyCut-to-active: 2actCut-to-poly: 2via1-to-via1: 3

via1-to-via2: 2via2-to-via2: 2via3-to-via3: 4

Metals: Metal-1 Metal-2 Metal-3 Metal-4 Metal-5 Metal-6

2-metals: 3 wide 3 wide3 apart 4 apart1 over via1 1 over via1

3-metals: 3 wide 3 wide 5 wide3 apart 3 apart 3 apart1 over via1 1 over via1/2 2 over via2

4-metals: 3 wide 3 wide 3 wide 3 wide3 apart 3 apart 3 apart 3 apart1 over via1 1 over via1/2 1 over via2/3 1 over via3

5-metals: 3 wide 3 wide 3 wide 3 wide 4 wide3 apart 3 apart 3 apart 3 apart 4 apart1 over via1 1 over via1/2 1 over via2/3 1 over via3/4 1 over via4

6-metals: 3 wide 3 wide 3 wide 3 wide 3 wide 4 wide3 apart 3 apart 3 apart 3 apart 3 apart 4 apart1 over via1 1 over via1/2 1 over via2/3 1 over via3/4 1 over via4/5 1 over via5

Note:All dimensions are given in lambda.

dost-asti electric manual

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