LINKS Also, the simulation test schematic must be named different from the symbol or the main schematic name. Open a new schematic. Follow the same procedure described in Schematic Capture to create a new schematic where you will put your simulation schematic for the inverter. Give a name to your new schematic which makes it clear that the new schematic is to simulate the inverter. The first step is to add and to place the components which will be used to simulate the inverter.
Connect the DC-voltage source "vdc" to "vdd" and "gnd". Connect the pulse wavefrom generator "vpulse" to the input of the inverter "In". Connect the load capacitance "cap" to the output of the inverter "Out". At the end of these steps, your entire schematic looks like the following.
Add labels to the nodes you want to observe after the simulation. Click on Analyses in the menu banner and select Choose. Note : Do not leave any space between the numeric value and the unit.
Do not type "s" after the unit where "s" stands for "seconds". Do not forget to type a unit after the numeric value, otherwise, the stop time for the simulation will be something in seconds which means your simulation will last forever!
Click on the nets which you want to observe in the schematic window. NOTE: Select the lines instead of a node. For example, select the line that goes from the pulse generator to the component. Start the simulation by clicking Simulation and then selecting Run or click on. If you are not satisfied with the simulation results, there are two different aspects that can be modified :.
Go back to the schematic window and select the symbol of your design. The symbol for the inverter should be selected in this example. Click on Edit in the menu banner, select Hierarchy and then Descend Edit. Click on OK in the Descend window which asks the designer which view of the design is to be edited.
Make the appropriate changes in the editable schematic of the design. Click on Edit in the menu banner, select Hierarchy and then Return.Remember Me? How can I put in the formula of Cin?
Thank you. Re: deviding Y value by X values in Cadence Virtuoso calculator. You have to apply imag for numerator. Generally Capacitance is nearly constant over frequency. Simply your equation is wrong. Originally Posted by Junus Simply apply imag in numerator.
If you plot complex value without applying any function, Cadence ViVA plots absolute value. Re: deviding Y value by X values in Cadence Virtuoso calculator Dear Pancho, Thank you again for your kind answer I am applying the "imag" function to the magnitude signal and the result are the same, it shows both have the exact value as you see from the third image result signal is the one with image fucntion applied below is the admitance in magnitude here I sent the signal to calculator here is the result after calculator Thank you very much.
See attached figure. Rather I suspect your test bench, since you still can not understand linear circut basics such as differentail mode, common mode, ideal transfomer and etc. Exporting expression values from cadence virtuoso 0. Part and Inventory Search.
Welcome to EDABoard. Design Resources. New Posts. Designing the buffer stage with minimum length transistor 3. Non isolated AC voltage sense 6.Authors: Jeannette Djigbenou and Meenatchi Jagasivamani. It allows the user to write a "script" to perform any command in Cadence.
SKILL was designed to work on repetitive tasks and several of its functions are based on lists. The objective of this procedure is to modify all nfet3 and pfet3 objects' bulk node value to be vss! This function is library specific and is given here as an example only. Building Nets, Terminals, and Pins.
The following steps show how to define pins in a layout. Create the shape that will serve as the pin. The shape is usually a rectangle. Note: The shape cannot be a polygon. Create the net to which the pin attaches. Create a terminal on the same net. The terminal must have the same name as the net and match the terminal type. The pin database object connects the pin figure with the net. The pin name can match the terminal name, but does not have to. In the example, the pin name n1 matches the terminal name.
Within the pcell, you can have multiple shapes that all belong to the same electrical terminal. Each shape would have a pin to associate it to the same net. In such cases, each pin is created on the same net and must have a unique pin name. The access direction is a list identifying the correct sides of the pin shape for connection.
Comments to: ha vt.Remember Me? Cadence corner simulation. By adding variable, I set VDD to be varied according to different corners.
By adding corners, I set the required corners, such as typical, ff and ss. However, after i run simulation and plot the VDD from the schematic, it's the same in all corners.
May I know anything missing in my setup? I can observe the variation of transistors. But I don't think VDD is included in the model file.
I did the same way as you. Do you mean to change the value of Vdc source for each corner, or the simulation will auto-change it according to each corner? Be carefull, as there is a lot of way to do the corners simulations, mainly depending of the design kit you use.
I hope this way work equally for you. In other hand, if this tools dosen't work properly, you may still write an "Ocean" script for yours simulations. Similar Threads monte carlo simulation,corner simulation,PVT simulation 7. How to set parameters for corner simulation in Cadence?
Corner analysis in Cadence Part and Inventory Search. Welcome to EDABoard. Design Resources. New Posts. Designing the buffer stage with minimum length transistor 3. Non isolated AC voltage sense 6. Please help power supply dead V to 24vdc 5vdc Why don't wind turbines have lighting protection rods extending up above them?
Fully differential amplifier with simple CMFB scheme on the differential pair Fully differential Op-amp with input common mode voltage different from the output 9. How can a lower supply voltage affect circuit performance?
Diodes dc bias on rat race mixer 3. Samsung GT-P Should I use it afterwards? Speaker difference between 8ohm and 45 ohm 2.
Current cource with LM?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. Hit 'YES' and continue.
This is the resulting graph.Remember Me? Global vdd and gnd vdd! I am using Spectre. By using "! They are recognized in different hierarchy in schematic simulation, so no problem. However, they are not recognized in layout extracted simulation. As you know, there are two common ways to use global nodes. One way is using vdd and gnd symbols and directly connects to a block of your circuits.
Another way is giving pins and name them vdd! In either way, there will be no physical nodes to connect to a power source and ground. Simulation in Spectre is no problem in another cellview as a testbench after replacing the symbol. However, the simulation won't work in layout because the global nodes are not recognized in different hierarchy.
For example, let's say an inverter with gnd! Then there will be no more physical nodes for vdd! After placing the symbol in a different cellvew as testbench for simulation, the result does not come out right. For easy test to check whether vdd! Then, the voltage of vdd is changed to 4v. However, the inverter output is still 2. As matter of fact, it does not invert the input signals. As soon as I change the simulation from the extracted to schematic, the signals are inverted at different voltage level which is 4v.
I believed that it would be the global bonding problem. Therefore, I used "Config" cellview from "Hierarchy Editor". It gave me the same wrong result. Some recommends using Verilog, but it requires some initial setup which I can't access.
Some recommends using ". CONNECT", but not available in our Cadence I have found some posts in this forum regarding to the same issues, but there is no such a good answer so far.
Anybody gives me a good solution Thank you. If you want the nets to be picked up in the extracted view, and called gnd! You can force pin-tagged nets without physical connection to be merged. I believe I've seen options that let you do this at top, or down levels of hierarchy. But when in doubt, hook it up realistically.Simulation of Vdd independent current source using Cadence Virtuoso ( Technologie 45nm )
You can put schematic pins with vdd! There is no such thing as a global layout node, with the possible exception of sub! Re: Global vdd and gnd vdd! Similar Threads Explanation of the global routing 1. Global routing and is detail and global router the same? Check my global declaration code Keil compiler 9. Part and Inventory Search.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.
In this case, you can see another instance is ready to be placed right after you placed the first instance. To terminate the current operation which is "add instance" in this casepress ESC key on the keyboard. In fact, you can always cancel the current operation in schematic or layout editors by pressing ESC key. Edit Object Properties:. Now, we set the length and width of the NMOS transistor that is instantiated.
An object properties editing form will pop up. In this form, make the NMOS width 1. The schematic should look similar to this:. Wiring up:. Click at the terminal where the wire starts and click at the terminal where the wire ends, a wire will be automatically added.
If you are not satisfied with the automatic wiring, you can remove the wire and reroute it manually. This time, instead of clicking at the terminal where the wire ends directly, you can click the left mouse button whenever you want to change the wire direction. If you want to stop the wire somewhere instead of connecting it to a terminal, double click your left mouse button and a dangling wire is created.