This is our Microwave Office tutorial series.
In this video we will use manufacturers Spice model datasheet and package Parasitics to model a diode
from scratch.
And we are going to use this model in the upcoming videos of diode mixer design.
So let's get started.
In the first step of this video we are going to open our design environment.
Let's create a new schematic.
To do that we'll go to Circuit schematic.
Right click new schematic.
We are going to name it Diode Model and click on create button.
Once the schematic has been created we'll go to elements.
Go to Nonlinear models.
From here we'll select diode and let's place spice Non-geometric junction diode.
In the schematic.
We are going to place it somewhere here.
Now in this diode model we are going to add the parameters from the Spice model provided by the manufacturer
okay.
This is one way of doing things.
There is another way we can place the place the Subcircuit here.
Import the spice module.
As we have already done in previous tutorials.
Right?
So here we are just going to add all the parameters manually.
To do that we'll just go back to the folder which you can download using the link given in the description.
From here we'll go to the spice module of diode.
And here you'll find the D315 V7 module.
We'll just open it on notepad.
And we are going to enter these parameters into the schematic.
All right.
So I'm going to do that quickly.
Now after adding all the parameters on this diode module we are going to add package Parasitics.
To do that again we will go back to the same folder.
And there you will find this sod 323. txt file.
If you open that on notepad you can see here we have the package Parasitics.
So this is our actual diode where we have added all the parameters.
And in that diode there there is some series inductors, parallel capacitors.
So we have to add those to make our diode model more accurate.
And here we have all the values as per those package Parasitics.
So we are going to add these package Parasitics first.
So I'm just going to close this.
Go back to viewer and to add the package Parasitics.
Or to add the components, we'll just hit Ctrl L on our keyboard and we'll search for inductor here
replace one inductor which will be in series with diode.
We'll just Ctrl c Ctrl v.
There will be one more inductor.
Ctrl C control V another inductor will be at the cathode of the diode.
Then we have to add one capacitor.
So go back to the library search for capacitor.
Click on okay and that will be parallel to the Diode.
We are going to just click over this Zoom Fit button.
Here we go.
Now I'm going to enter the values from the the Parasitics model shared by the manufacturers.
To do that we'll just add these equations.
So the Lao value was 0.65.
I'll just copy this control c control v.
Then another parameter was l a and the value was 0.76.
And these all values will be in Nano Henry.
So just remember that.
Then there will be another variable which will be ae.
And the value of that will be 0.69 Henry.
And then there was another capacitor.
So I'm just going to place it here.
And the variable name was CAC.
And its value was .12 Picofarad.
Here we go.
Now we are going to assign these variables.
So let's place those somewhere here so we can see that.
Okay.
Now we are going to assign these variables to these inductors.
So this will be L this will be AC.
The name of this variable is l a I.
So let's make that and this will be ae.
There we go.
Next we are going to add the input and output port before running the simulation.
Now to add the port we'll just click over this port button from the toolbar.
We'll place it here.
Right click Ctrl C Ctrl V rotate the port.
Let's place this text here.
And then we are going to connect these components as well.
All right so here we here we have our diode model with package parasitics for this port.
So since this will be the anode of the diode.
So I'm just going to change the port ID to a node here.
And similarly I'm going to add the port ID for another port.
Let's make it cathode.
So as of now our diode model is ready.
In the next step of this video we are going to prepare the diode model for I-V curve Testbench.
All right.
Now to do that we are going to create another schematic.
So let's right click Create new schematic.
I'm going to name it diode I-V curve and click over create button.
Next we are going to place the Subcircuit uh of the diode model that we have created.
To do that we'll just click over here.
And this is the two port model that we are going to use.
So we'll place it here.
This is anode and cathode.
And we are going to assign the diode model on this rectangular block.
To do that we'll double click go to symbol.
And here we have to find the diode IC.
So let's scroll down and here we go click okay.
So we have assigned the correct symbol to this Subcircuit block.
Now we are going to add the ground at the cathode side.
And next we are going to place the measurement device which is I-V curve.
To do that we'll again go back to library.
And here we are going to search for I-V curve.
So let's search.
Okay.
This is the one that we are going to use.
We'll place it somewhere here.
Next we are going to change the value.
So stop voltage will be one volt.
And the step size.
Let's make it 0.1V and let all the other parameters as by default we are going to connect the sweep
port to the anode of the diode.
And the step we are not going to set any, uh, step.
Externally.
So we'll just let it be like that.
In the next step of this video, we are going to create the new graph.
To do that.
We'll click our graph new graph.
Make sure you have selected rectangular here.
Click over create button.
Next we are going to add measurements.
To do that we'll click over add measurements go to Nonlinear Measurements.
And here we have to select current and.
In the measurement we have to select I-V curve which is here.
So as you can see in the description this this will plot for I-V curve trace I at the sweep terminal.
Make sure we have to select the correct data source name.
So in our case it will be diode I-V curve.
Make the I-V curve step to zero volt and click over.
Add and close it.
And we are good to go for running the simulation.
To do that we just click over this simulate button.
All right so here we have the I-V curve for the diode.
And to verify that we'll open the datasheet of the diode.
So from the datasheet we are going to verify the forward voltage at a particular forward current.
So to do that we are going to add the marker.
And we are going to add marker at one milliamps of current.
And then we'll see what is the voltage at one milliamps of current.
So for now just add the marker here.
We'll double click here and we'll right click our marker.
Click our marker search.
We are going to find the value on y axis.
And let's search the value.
Let's say one milliamp and click over search.
Okay.
So as you can see at one milliamp the forward voltage is 0.2366, which is sort of between the minimum
and the maximum value of the forward voltage given on the data sheet.
As you can see on your screen, and it is very close to the typical value.
Similarly I want to search for ten milliamps.
So as you can see at ten milliamps the value is 0.3685V, and which is again close to the typical value
given on the datasheet.
All right.
So we have modeled the Bad 15 diode which acts like a real diode.
Now in the next tutorial we are going to use these diodes in the single diode mixers.
And we'll see the simulation results of that mixer.
Next we are going to save the project.
To do that.
First we will just cancel this go to File Save project I am going to save it on desktop save button.