Crash Course: TDR Analysis using SIwave and AEDT Circuit
Introduction
This guide provides a step-by-step process for conducting Time Domain Reflectometry (TDR) analysis using SIwave and AEDT Circuit. Follow the instructions to effectively upload your design and analyze it using the TDR wizard.
Uploading Your Design
- Start by uploading your design.
- Click on the designated area to view supported file types.
- SIwave supports file types such as IPC 2581 or ODB++.
Simulation Setup
- Navigate to the simulation section and select the TDR Wizard.
- Select the line you want to study for the TDR analysis.
- Remember to select from the following options:
- Differential
- Extended
- Extended Differential
- Proceed to the next step.
Specifying TDR Probe and Termination
- For each line, specify the location for the TDR probe.
- Select the TDR probe and the termination point.
- Proceed to the next step.
Signal Configuration
- Specify the signal parameters for each probe:
- Rising Time
- Pulse Width
- Ensure the pulse width is significantly longer than the structure's length.
- Set the impedance of the port, e.g., 35 picoseconds for this port.
- Choose a rising time that allows visibility of different transitions within the model.
- At the bottom, specify the termination, which is the other side of the setup.
- Proceed to the next step.
Viewing Results
- Specify where you want to view the results, such as in the electronic desktop.
- This section is crucial as SIwave functions as an S-parameter solver, similar to other EM solvers.
- After solving the problem, proceed to the next section.
S-Parameter Solver
- After solving the S-parameter, it performs the FFT and switches to the time domain.
- Specify the bandwidth of the S-parameter solver:
- Start from zero frequency.
- The higher frequency correlates with the rising time.
- Select a rising time smaller than the TDR's rising time.
- Press OK and solve the problem.
Solution and Results
Once the solution is obtained, you can plot and analyze the results.
Start by uploading your design. If you click here, these are the file types SIWave can support, especially IPC 2581 or ODB++. Go to simulation and select TDR wizard. Select which line you want to study to do the TDR. Remember you still have differential, extended, and extended differential.
You have to select them. Go next. In each side, for each line, you have to specify where to put the TDR probe. Here, select the TDR probe and the termination. Go next. Specify the signal you are using to do the TDR for each probe. So, specify the rising time and pulse width.
Usually, the pulse width should be way longer than the length of the structure. This is the impedance of the port (35 picoseconds for this port). The probe, for example, for the rising time, is selected in such a way that I am able to see the different transitions inside the model.
At the bottom is the termination, which is the other side. Specify where you want to see the results. You can see them in the electronic desktop. This section is the most important section. SIWave is an S-parameter solver like any other EM solver.
After solving the problem, you can go to the next section. This is the S-parameter solver. After solving the S-parameter, it does the FFT and switches to time domain. Specify the bandwidth of the solver, the S-parameter solver. In this case, notice you have to start from zero.
The higher frequency here is related to the rising time. In our case, we do not just select the similar rising time as the TDR itself. We select something smaller. Press OK and solve. Now that we have a solution, we can plot the results here.
