WEBVTT 00:00.720 --> 00:03.760 This is our Microwave Office tutorial series. 00:03.760 --> 00:11.120 In this video we will use manufacturers Spice model datasheet and package Parasitics to model a diode 00:11.120 --> 00:11.920 from scratch. 00:12.800 --> 00:17.720 And we are going to use this model in the upcoming videos of diode mixer design. 00:17.720 --> 00:18.960 So let's get started. 00:19.160 --> 00:23.360 In the first step of this video we are going to open our design environment. 00:23.480 --> 00:24.760 Let's create a new schematic. 00:24.760 --> 00:26.720 To do that we'll go to Circuit schematic. 00:27.080 --> 00:29.000 Right click new schematic. 00:29.600 --> 00:33.280 We are going to name it Diode Model and click on create button. 00:33.760 --> 00:36.600 Once the schematic has been created we'll go to elements. 00:37.280 --> 00:38.920 Go to Nonlinear models. 00:39.280 --> 00:44.840 From here we'll select diode and let's place spice Non-geometric junction diode. 00:45.120 --> 00:46.160 In the schematic. 00:46.200 --> 00:47.960 We are going to place it somewhere here. 00:48.760 --> 00:55.440 Now in this diode model we are going to add the parameters from the Spice model provided by the manufacturer 00:55.800 --> 00:55.960 okay. 00:56.000 --> 00:57.600 This is one way of doing things. 00:58.000 --> 01:00.530 There is another way we can place the place the Subcircuit here. 01:00.650 --> 01:01.970 Import the spice module. 01:02.010 --> 01:04.290 As we have already done in previous tutorials. 01:04.410 --> 01:04.850 Right? 01:05.330 --> 01:09.650 So here we are just going to add all the parameters manually. 01:10.250 --> 01:16.970 To do that we'll just go back to the folder which you can download using the link given in the description. 01:17.970 --> 01:21.890 From here we'll go to the spice module of diode. 01:22.010 --> 01:25.770 And here you'll find the D315 V7 module. 01:26.130 --> 01:27.770 We'll just open it on notepad. 01:29.450 --> 01:33.690 And we are going to enter these parameters into the schematic. 01:33.970 --> 01:34.610 All right. 01:34.610 --> 01:36.090 So I'm going to do that quickly. 01:36.810 --> 01:42.330 Now after adding all the parameters on this diode module we are going to add package Parasitics. 01:42.450 --> 01:45.050 To do that again we will go back to the same folder. 01:45.530 --> 01:49.890 And there you will find this sod 323. txt file. 01:50.730 --> 01:55.330 If you open that on notepad you can see here we have the package Parasitics. 01:55.650 --> 01:59.570 So this is our actual diode where we have added all the parameters. 02:00.010 --> 02:05.170 And in that diode there there is some series inductors, parallel capacitors. 02:05.650 --> 02:09.610 So we have to add those to make our diode model more accurate. 02:09.930 --> 02:14.170 And here we have all the values as per those package Parasitics. 02:14.530 --> 02:17.410 So we are going to add these package Parasitics first. 02:17.690 --> 02:19.610 So I'm just going to close this. 02:20.170 --> 02:23.570 Go back to viewer and to add the package Parasitics. 02:23.770 --> 02:30.570 Or to add the components, we'll just hit Ctrl L on our keyboard and we'll search for inductor here 02:30.610 --> 02:34.450 replace one inductor which will be in series with diode. 02:35.850 --> 02:38.490 We'll just Ctrl c Ctrl v. 02:38.930 --> 02:40.290 There will be one more inductor. 02:40.650 --> 02:46.330 Ctrl C control V another inductor will be at the cathode of the diode. 02:47.090 --> 02:49.290 Then we have to add one capacitor. 02:49.650 --> 02:52.970 So go back to the library search for capacitor. 02:53.810 --> 02:57.540 Click on okay and that will be parallel to the Diode. 02:58.540 --> 03:00.900 We are going to just click over this Zoom Fit button. 03:01.740 --> 03:02.260 Here we go. 03:03.980 --> 03:10.060 Now I'm going to enter the values from the the Parasitics model shared by the manufacturers. 03:10.340 --> 03:13.540 To do that we'll just add these equations. 03:14.500 --> 03:19.540 So the Lao value was 0.65. 03:20.100 --> 03:22.620 I'll just copy this control c control v. 03:23.300 --> 03:31.540 Then another parameter was l a and the value was 0.76. 03:31.860 --> 03:34.500 And these all values will be in Nano Henry. 03:34.540 --> 03:35.780 So just remember that. 03:36.940 --> 03:42.300 Then there will be another variable which will be ae. 03:42.300 --> 03:45.420 And the value of that will be 0.69 Henry. 03:45.540 --> 03:47.500 And then there was another capacitor. 03:47.500 --> 03:48.980 So I'm just going to place it here. 03:49.700 --> 03:54.460 And the variable name was CAC. 03:54.500 --> 03:57.980 And its value was .12 Picofarad. 03:59.260 --> 03:59.820 Here we go. 04:00.140 --> 04:03.260 Now we are going to assign these variables. 04:04.500 --> 04:08.380 So let's place those somewhere here so we can see that. 04:08.940 --> 04:09.420 Okay. 04:09.420 --> 04:12.740 Now we are going to assign these variables to these inductors. 04:13.260 --> 04:17.340 So this will be L this will be AC. 04:17.740 --> 04:20.220 The name of this variable is l a I. 04:20.620 --> 04:25.660 So let's make that and this will be ae. 04:25.700 --> 04:26.220 There we go. 04:26.580 --> 04:31.500 Next we are going to add the input and output port before running the simulation. 04:32.220 --> 04:36.980 Now to add the port we'll just click over this port button from the toolbar. 04:37.020 --> 04:38.100 We'll place it here. 04:41.260 --> 04:46.260 Right click Ctrl C Ctrl V rotate the port. 04:47.140 --> 04:49.620 Let's place this text here. 04:49.980 --> 04:52.780 And then we are going to connect these components as well. 04:53.380 --> 04:58.950 All right so here we here we have our diode model with package parasitics for this port. 04:59.110 --> 05:01.430 So since this will be the anode of the diode. 05:01.790 --> 05:07.030 So I'm just going to change the port ID to a node here. 05:07.070 --> 05:10.590 And similarly I'm going to add the port ID for another port. 05:11.390 --> 05:12.870 Let's make it cathode. 05:13.550 --> 05:15.910 So as of now our diode model is ready. 05:16.230 --> 05:23.230 In the next step of this video we are going to prepare the diode model for I-V curve Testbench. 05:23.270 --> 05:23.870 All right. 05:24.430 --> 05:28.030 Now to do that we are going to create another schematic. 05:28.510 --> 05:32.710 So let's right click Create new schematic. 05:33.070 --> 05:37.910 I'm going to name it diode I-V curve and click over create button. 05:38.350 --> 05:44.630 Next we are going to place the Subcircuit uh of the diode model that we have created. 05:44.790 --> 05:47.110 To do that we'll just click over here. 05:47.630 --> 05:50.590 And this is the two port model that we are going to use. 05:50.950 --> 05:52.310 So we'll place it here. 05:52.670 --> 05:54.160 This is anode and cathode. 05:54.960 --> 05:58.800 And we are going to assign the diode model on this rectangular block. 05:59.080 --> 06:01.600 To do that we'll double click go to symbol. 06:02.200 --> 06:04.880 And here we have to find the diode IC. 06:05.560 --> 06:10.160 So let's scroll down and here we go click okay. 06:11.640 --> 06:14.800 So we have assigned the correct symbol to this Subcircuit block. 06:15.360 --> 06:20.160 Now we are going to add the ground at the cathode side. 06:21.080 --> 06:25.520 And next we are going to place the measurement device which is I-V curve. 06:25.560 --> 06:27.520 To do that we'll again go back to library. 06:28.120 --> 06:31.240 And here we are going to search for I-V curve. 06:32.240 --> 06:33.560 So let's search. 06:33.720 --> 06:34.120 Okay. 06:34.160 --> 06:35.880 This is the one that we are going to use. 06:36.320 --> 06:37.720 We'll place it somewhere here. 06:38.520 --> 06:39.960 Next we are going to change the value. 06:39.960 --> 06:42.160 So stop voltage will be one volt. 06:42.440 --> 06:43.440 And the step size. 06:43.440 --> 06:50.960 Let's make it 0.1V and let all the other parameters as by default we are going to connect the sweep 06:51.000 --> 06:53.560 port to the anode of the diode. 06:54.320 --> 06:59.520 And the step we are not going to set any, uh, step. 06:59.840 --> 07:00.520 Externally. 07:00.520 --> 07:02.080 So we'll just let it be like that. 07:03.640 --> 07:06.840 In the next step of this video, we are going to create the new graph. 07:06.840 --> 07:07.200 To do that. 07:07.240 --> 07:10.200 We'll click our graph new graph. 07:11.480 --> 07:13.320 Make sure you have selected rectangular here. 07:15.400 --> 07:16.680 Click over create button. 07:17.080 --> 07:18.680 Next we are going to add measurements. 07:18.680 --> 07:23.320 To do that we'll click over add measurements go to Nonlinear Measurements. 07:24.000 --> 07:29.600 And here we have to select current and. 07:31.840 --> 07:36.920 In the measurement we have to select I-V curve which is here. 07:37.360 --> 07:44.680 So as you can see in the description this this will plot for I-V curve trace I at the sweep terminal. 07:45.240 --> 07:49.600 Make sure we have to select the correct data source name. 07:49.720 --> 07:52.930 So in our case it will be diode I-V curve. 07:53.890 --> 07:57.730 Make the I-V curve step to zero volt and click over. 07:57.770 --> 07:59.370 Add and close it. 08:00.050 --> 08:02.330 And we are good to go for running the simulation. 08:02.490 --> 08:05.890 To do that we just click over this simulate button. 08:05.930 --> 08:10.650 All right so here we have the I-V curve for the diode. 08:11.410 --> 08:14.610 And to verify that we'll open the datasheet of the diode. 08:15.450 --> 08:22.810 So from the datasheet we are going to verify the forward voltage at a particular forward current. 08:23.370 --> 08:25.730 So to do that we are going to add the marker. 08:26.170 --> 08:31.690 And we are going to add marker at one milliamps of current. 08:31.690 --> 08:34.850 And then we'll see what is the voltage at one milliamps of current. 08:35.090 --> 08:36.850 So for now just add the marker here. 08:37.170 --> 08:39.970 We'll double click here and we'll right click our marker. 08:40.170 --> 08:41.450 Click our marker search. 08:41.890 --> 08:44.250 We are going to find the value on y axis. 08:45.170 --> 08:47.490 And let's search the value. 08:47.530 --> 08:50.210 Let's say one milliamp and click over search. 08:50.890 --> 08:51.290 Okay. 08:51.650 --> 09:00.090 So as you can see at one milliamp the forward voltage is 0.2366, which is sort of between the minimum 09:00.170 --> 09:04.170 and the maximum value of the forward voltage given on the data sheet. 09:04.370 --> 09:08.370 As you can see on your screen, and it is very close to the typical value. 09:09.090 --> 09:12.570 Similarly I want to search for ten milliamps. 09:12.890 --> 09:22.050 So as you can see at ten milliamps the value is 0.3685V, and which is again close to the typical value 09:22.050 --> 09:23.210 given on the datasheet. 09:23.250 --> 09:23.770 All right. 09:24.250 --> 09:29.450 So we have modeled the Bad 15 diode which acts like a real diode. 09:29.730 --> 09:36.090 Now in the next tutorial we are going to use these diodes in the single diode mixers. 09:36.090 --> 09:40.370 And we'll see the simulation results of that mixer. 09:40.450 --> 09:41.810 Next we are going to save the project. 09:41.810 --> 09:42.450 To do that. 09:42.450 --> 09:49.490 First we will just cancel this go to File Save project I am going to save it on desktop save button.