Cadence Tutorial
HSpice Netlist Extratction with
Cadence
Authors: Jeannette Djigbenou, Jos
Sulistyo, Meenatchi Jagasivamani, Carrie Aust
This tutorial explains how to extract
a HSPICE netlist from your cellview from either the schematic or layout view.
- From Virtuoso
(the layout view):
a) Get the extracted view of the layout: - Select Verify -> Extract.
- To extract parasitic capacitances
for NCSU kit:
- Click the Set Switches button.
- Select Extract_parasitic_caps option. If you use capacitors or
resistors, like in many analog applications, select Extract_cap
and
Extract_resistor also.
- In the CIW, type "NCSU_parasiticCapIgnoreThreshold=x" with x
being the maximum value of capacitance to ignore (in Farads); 1e-18 is a
typical value.
- Leave all other options as default.
- Click
OK.
- Click
OK.
b) Start Analog Artist:
Select Tools -> Analog Environment from the
extracted window.
c) Go to Netlist
Extraction Procedure below.
- From Composer (the
schematic view):
a) All nodes must be named first - unless you are satisfied with automatically-generated names / node numbers. If they are not already named, left click each node (or wire connected to the node), then choose Edit -> Properties -> Object
b) Start Analog Environment: Select Tools -> Analog Environment -> Simulation from the command (CIW) window.
c) Go to Netlist Extraction Procedure below.
- NOTE: When
using both switch-level and gate-level logic in a
schematic
- Extract standard cells
corresponding to the gates in your schematic
a) Open the extracted view of a standard cell in Cadence Virtuoso.
b) Follow
instructions for extraction from layout given in the Netlist Extraction Procedure below. The
HSPICE netlist is the subcircuit definition of the corresponding gate. (Ex: wand2_2.sp)
- Extract schematic for Netlist
using instructions given in the Netlist
Extraction Procedure below.
- Include the subcircuit definition
in the top-level circuit HSPICE file using a .include statement. (Ex: ?.include
?./wand2_2.sp??)
Netlist
Extraction Procedure
From Analog Artist:
(Note:
You must have the extracted view open in the background)
- Select Setup->Simulator/Directory/Host.
a) Select the hspiceS simulator.
b) Set your project
directory. This will be where all your files will be created.
- Select Setup->Design
a) Library name: (your library
name)
b) Cell Name: (your cell name)
c) View Name: Extracted OR
Schematic, depending on whether you started with layout or schematics
d)
Open Mode: Read
Click OK to close the window.
- Select Setup->Environment.
a) Insert "extracted" before "hspiceS" on the Switch View List if you started with layout; if
you started with schematic, insert "schematic" instead if not already there, but it
should be already there.
b) Insert "ivpcell" before "hspiceS" on the Stop
View List.
c) Select the Include
File Syntax to be hspice.
- Create
Netlist.
a) Select Simulation -> Netlist -> Create Final.
c) Save the file displayed. This is the
HSPICE netlist of your design.
- If your circuit
is very large, you may get
OUT OF
MEMORY errors. If
this is the case, add the following three lines to your ~/.cdsenv file:
cdsSpice.init
languageSize int
500
spectreS.init
languageSize int
500
hspiceS.init
languageSize int
500
- Exit Analog Artist: Select
Session -> Quit.
- When asked if you wish to save current state, click
No.
Special Note about Pin
Names:If you have defined your
pin names to have more than 16
characters,
this exceeds the HSPICE label limit. In your extracted netlist, that node
will be assigned to a number instead. (See the section on Creating I/O Pins...)


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