Double click each variable and set its value as you wish. Choosing Analyses window will appear. This is where you have options to run many different types of analysis. Choose tran from "Analysis" and give a simulation time. Specify Sweep Range and Type. Before you start the simulation, let's add outputs to be plotted.
The node name will show up in Output section. Make sure you hit "Check and Save" button from the left toolbar in Schematic Editing window and run simulation by hitting "green" traffic signal on the right toolbar in ADE window. You will be able to see a run log file and output graphs.
Let's calculate a voltage gain to finally measure 3 dB bandwidth while sweeping L values. The Setting Outputs window will pop up. The Calculator window will show up. We are going to measure AC voltage. We will now measure a node voltage on the schematic. If you want to calculate dB20 because it is a voltage gain not power gainclick dB20 in the filter box. Repeat same method to calculate Vin in dB20 scale and subtract it from Vout in dB Go back to Setting outputs windowclick Get Expression from Calculator.
The defined expression will show up in Expression box. Three graphs will be plotted if you run your simulation again. According to the Table 1.
Let's calculate some inductor values before sweeping L values in the simulation. The L value for the maximum bandwidth will be calculated around 7. Let's sweep the L values. Parametric Analysis window will pop up.
You can make several sweeps for your simulation. We will sweep only one variable, L, at this point. After 9 runs sweeping L values from 0 to 8 nH with 1 nH step, we will get 9 plots. Let's zoom in frequency between 1 GHz and 10 GHz by clicking zoom-in button on the top-menu. I'll leave calculations of normalized bandwidth values for other conditions.
If you have any question regarding on this tutorial, please feel free to contact me, Jihoon Jeong. Dong S. Figure 7. Assign design variables in ADE 2. Figure 8. Choose Transient Analysis 3. Figure 9. Choose AC analysis and specify options 4.
Figure Creating Circuit Schematic. Symbol Creation and Simulation. Layout instantiations. Padframe Information. Waveform Calculator Tutorial. If they are not, please refer to the Cadence Setup page for this procedure.
Creating New Library:. Now the library Lab1 is created. Creating new schematic design. If the Upgrade License window appears, click Yes. The Virtuoso Schematic L tool appears, as shown below:. At this point, you have created a library called Lab1 and a cell inside it, called inverter. Now the design process can be started.
For a full custom design, the process begins by creating a schematic. Then we simulate this design to verify the correctness of its functionality. Only after this is doneis the layout of the design performed. Now, we put down the design of the inverter in the Schematic Editor window. The transistors and the input signal sources are instantiated and connected in the schematic editor. To instantiate a NMOS transistor :.
Create Instance:. The " Add instance " dialogue box appears together with the "component Browser" dialog box. In case the "Component Browser" does not appear, click on browse in the "Add Instance" dialog box to start it. To place the instance, activate the schematic window and click the left mouse button to put the instance at the place desired.
Note in Cadence schematic composers and layout editors, a command will not terminate unless the user cancels it or the user starts a new command.Start by creating a new schematic cell view in you existing or newly created library. Create a new schematic cellview where we shall instantiate a NMOS and apply some Vgs and Vds and plot the drain currents at different operating points.
This will invoke a new subwindow called Add an instance window. Here we can select what we wish to add to the schematic.
AC Analysis in Advanced Design Environment (ADE)
A window shown below will appear where can can change the W and L of the transistor and even rotate the transistor in all ways and direction by the Rotate, Sideways and Upside Down keys.
After placing the transistor, the schematic would look something like this. The top terminal of the NMOS is the drain, bottom one is the source clear from the arrowthe terminal on the left is gate and on centre right is body.
Now we have to add dc supply sources. One Vdc source for gate to source voltage and one for drain to source voltage. Note that analogLib can be sorted by categories by ticking the show category option at the top of the browser window. Draw the schematic as shown below.
NOTE that a gnd! Else the simulator will not be able to resolve the voltages as no reference would be specified then. Now the value of the dc sources as to be set. This is open the query page. Note that no units are to be added. Cadence will automatically take it in voltage. Also the W and L of the transistor can be changed at any time by selecting the transistor and pressing q.
This will check for errors and save and will report if there are any errors or warnings. Errors cannot be ignored but warnings may be ignored if you are aware and sure that the warning is harmless. Now its time to simulate. A new window opens up. Immediately, vgs and vds would appear on the low left side of this window.
Also select component parameter below. Click on select component twice. This will take you to schematic, click on a voltage source for vgs, then in new popup window select dc voltage and then OK.
Then press OK on analysis window. Now select the drain terminal of the NMOS transistor by clicking on it. The Final analysis window will look like shown below. Now simulation will start and a plot window will appear as shown below. The Id Vgs curve shown above is for the specified value of vds specified to variable vds in analog environment window.
We can also plot Id Vgs characteristics for more than one value of Vds on the same graph at the same time. Such plots can be achieved by parametric analysis. Let us consider that we wish to plot the below given graph. Each curve on the plot is for different values of Vds. Therefore we select vgs as the sweep variable in dc analysis and vds as the variable of parametric analysis. Just like earlier, from analog environment, we select vgs voltage source in component parameter sweep in DC Analysis.
Sweep it from 0 to 1.University of Kentucky. Department of Electrical and Computer Engineering. Cadence University Program Member. This tutorial shows how to do a dc sweep analysis with Spectre. To begin, bring up a new blank Spectre schematic window. Add a 'nfet' instance from the tech library. From the analogLib, add an instance of 'gnd'. This is the reference point for your circuit. All voltages will be relative to this point. Again from the analogLib, add an instance of 'vdc'.
This is a simple DC voltage source. Change the voltage value to 1. Add another instance of this voltage source. Edit the properties of the first voltage source. Change the name of the instance to 'VGS'. We choose this name to make it easier to tell the instances apart from each other when we are setting up our analysis later. Do the same with the next voltage source, except call it 'VDD'.
Add in another instance of 'vdc' from the analogLib.
This time give it a voltage value of 0. This instance allows us to later probe the current going throgh this branch the drain current. Open up the analog lib. Setup the model libraries and simulator to the values used for transient analysis.
If you attempt to change the 'Stimuli' for this setup you will see this error. Choose your analysis as 'dc' instead of the usual 'tran'. This will allow us to sweep any dc model parameter in the circuit. Go to the sweep variable portion of the window. Click 'Component Parameter'. Click 'Select Component'. Choose the VGS source on the schematic. This is the instance that we want to sweep.
Set the range of the voltage sweep. For this example, it is. Make sure that the dc analysis is enabled and hit OK to close the window. Using the standard plot selection methods, choose the node that you want to plot.
Your design window should now look like this.
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Hit 'YES' and continue. This is the resulting graph. If you don't see something like this, then something is wrong with your setup.Remember Me? I've got my circuit functioning and have a plot of the transient performance of the circuit for a set control voltage.
What I'd like to do is sweep my control voltage and generate a plot of voltage vs. At the moment I have the equation to calculate my frequency for fixed voltage and it works fine. I just need to figure out how to now sweep the voltage and generate my plot. Hope my question is clear.
Any help greatly appreciated! What I don't know is a function to plot frequency versus each voltage stepped in the PA. Also, I think I'll need some way of not calculating the frequency for each step until after a so many nano seconds to allow for settling of my oscillator. Originally Posted by InspectorGadget.
Ok, I've figured out that what I need is a parametric analysis and I know how to run this. Similar Threads how to plot controls voltage versus power consumption in cadence 1. How to plot the parameter region after DC sweep in Cadence? Cadence simulation - Voltage Vs Gain plot Define a voltage function in Cadence Virtuoso How to plot Vt threshold voltage Vs. Part and Inventory Search. Welcome to EDABoard.
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The stability of the power amplifier 1.Remember Me? Set AC magnitude to 1mV or 1V. Run AC analysis. It will plot input impedance vs. Use mouse, calculator window CW and schematic window SW. The expression in CW will be changed. Similar Threads how to plot a filter whose input is a chirp signal?
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How to simulate a n-p-n bjt using Cadence Virtuoso? Ask Question. Asked 3 years, 11 months ago. Active 3 years, 11 months ago. Viewed 1k times. Need help. I'd also like to mention that I'm using the spectre tool. Active Oldest Votes. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog.
AC Analysis in Advanced Design Environment (ADE)
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