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How to know that ALL MOS are in saturaion region in Cadence?

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Jan 31, 2005
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cadence transistor region

How to know that ALL MOS are in saturaion region in Cadence?

so far I would like to use "Circuit conditions" menu but Circuit conditions check is not reliable because Circuit conditions check only All mos are in Linear region or not.

what is your method to know that where are All MOS in ??


cadence region of operation

Maybe u can try to use Annotate voltage on the schematic in conjunction with Circuit conditions to increase your confidence level. If you would like to go into ocean or skill programming, write some script to sweep through all the devices' bias voltage.

cadence mos region

could you explain me in detail?

I don't know what you mean exactly.

circuit condition menu only used "numbers", not parameter like vgs, vds etc


cadence region=2 saturation

In ADE choose Results > Anotate > DC Operating Point
then choose any MOS of which u want the op pt condition.


    Points: 2
    Helpful Answer Positive Rating
ocean scripts op region

I think spectre deliver a operation point region information in the raw file. The ouput parameter is called "region" and could have numbers 0-4 with meaning (off, triode, sat, subth, breakdown). I could possible be annotated as a string with the meaning above.
cadence operating region 4

Hi vbhupendra and rfsystem,

I use ADE 5.0.33 release, and I can print the DC Operating Point but I cannot use this DC Operating Point annotation feature, so I am wondering whether this feature depends on ADE version and/or spectre model.

Also I cannot find the operation point region information neither in the raw file and the printing dc operation point form. What is the root of this problem?



cadence regions of operation

what do you think of this method ?

vdsat ocean

Hi 020170,

Could you tell more details about your method? Thanks!


spectre mos region

There are more than one ways to see the region of operation of transistor.
I have used it in ac analysis and can see the dc operating conditions.
AA-> Results -> DC operting points. On the schematic window Edit -> component Display -> parameter (you can select Vdsat, Vds, gm, Vgs, Vth). From the values of Vdsat and Vds you can figure out the region of operatin of transistor.

printing the region using ocean script

thanks bsrivastava!

Is there anyone who knows better method than my method?

cadence operating region


could you specify what is the intention of the method. As I understand you can use a graphic feedback or a script listing region attribute. But what you want to do with this info.

Did you have a list op op-modes of your circuit and want to verify region if the circuit is external embedded?

Or other intentions?

regions of operation in cadence


There is one simple method to check component values(Vdsat,gm,Id,Cgs,Cgd,........).first peform DC analysis.after that open caliculator.there select (op) button in caliculator which is operational parameters.after clicking on (op) button a new window open saying select a component from schematic .select a requiered component in schematic.In the old
window u can get list.there u can see all values of your transistor

cadence circuit conditions

If the number of transistors are large, u can use an OCEAN script and write the operating regions to any file.

cadence dc operating point region

Yes OCEAN script is powerful tool to know all mosfet is saturation or not.

but it is not easy work. because OCEAN script example is not enough in the internet.

so I don't know how I write OCEAN script to know ALL MOSfet is SAT or LIN, etc.

Could you explain me how to write OCEAN script to know region of MOSfet ?


cadence 4 regions

Hi every one,

I am a freshmen of caden. Can you explain me the way to write OCEAN script?


cadence dc operation print region

The simplest way to learn how to write Ocean Scripts, is to do the following.

- Create ur full Schematic Entry.
- Run Vitousu Analog Environment
- Perform ur Simulation settings being either DC, AC, or STP associated with parametric weep.
- From "Session" Tab, Choose "Save as a script", Select where to save ur ocean file, and give it an a name, say "save.ocn", let's say u dropped it @ "home/user/save.ocn"
- go to "home/user/save.ocn" then open it, and learn the syntax for the simulation settings u already performed.
- Actually it's awesome way for learning scripts u made urself.

region dc print mos

Most simplest way is to use Device Checking tool in ADE. Of cource by myself I prefer to do annotating both node voltages and OP parameters on schematic (like Richlo proposed) because it gives the best insight in circuit operation.
"The Analog Design Environment is now enhanced to support Spectre’s device checking
capability. This capability allows you to determine if elements in your circuit are violating
predefined safe operating areas. The rules can include checks of operating point parameters,
as well as expressions that combine these parameters. These checks can be part of your
model card, netlist, or any other file that is included for simulation as a part of the design. A
graphical user interface is available for you to add/modify device checks, run Spectre with
device checks and see violations. You can print a summary of all the violations, highlight
violating devices in the schematic and obtain all violations for any device in the schematic.
Filters can be used to reduce the number of violations printed/devices highlighted.
To access this feature, click Simulation ->Device Checking in the simulation window."

regions of device in ocean script

Dear 020170,

get the operating points and there should be a "region" parameter. a number 2 means it is in saturation region.

- Al

How to know that ALL MOS are in saturaion region in Cadence

Dear all,

Can you tell me more about the region parameter ?
What does 0 to 4 represent in the region parameter?

Thank you.
Re: How to know that ALL MOS are in saturaion region in Cade

hi wing0,

here the meanings of the numbers:

0 ... cutoff
1 ... linear
2 ... saturation
3 ... subthreshold
4 ... breakdown

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