SIwave: Everything you need to know about the TDR Wizard (HD version)
In this video, we discuss the TDR Wizard and its features within SIwave, a tool for power integrity and signal integrity analysis. The TDR Wizard is essential for examining the impedance of PCB traces, detecting discontinuities, and identifying issues with transitions, particularly via transitions.
Introduction to TDR Simulation
TDR (Time Domain Reflectometry) is derived from S parameters and is part of the SYZ or PI solver. SIwave performs fast and accurate TDR calculations for hundreds of traces on large boards, outperforming other software in this regard. However, SIwave is not recommended for PCB design.
Supported CAD File Imports
- IPC 2581
- ODB++
- DXF
- GDS
- ADB (with an ANSYS translator)
Upon uploading a file, SIwave extracts information such as the stackup, materials, components, and nets.
Using the TDR Wizard
- Select a Solver: Begin any process in SIwave by selecting a solver, which generates a dialog box for user input.
- Trace Selection: Choose traces from the list on the left. For example, traces N17055, N5555, and PB_WR can be selected.
- Specify TDR Probes: Assign a TDR probe and termination for each trace. For differential lines, select both positive and negative probes and terminations.
- Signal Specifications: Define the rising time, pulse width, and pulse period for the TDR analysis. The pulse width should be longer than twice the trace's length, and the pulse period should be double the pulse width.
- Define the Solver: Name your solution and choose between generating a netlist or a schematic. The schematic option allows for further TDR analysis.
Transient Simulation
After simulating the S parameters, specify the step size and stop time for the transient analysis. The stop time is typically equal to the pulse width, and the step size is 1/5th or 1/10th of the rising time.
S Parameter Options
Define the frequency band for the S parameter solution, starting from zero. Adjust the minimum rising time based on the frequency band. Set solver accuracy options for balanced, more accurate, or faster results.
Results and Analysis
SIwave generates a schematic in the electronic desktop, showing terminations and TDR probes. You can modify the schematic, add sources, and analyze voltage and TDR plots. For example, a line with a 60-ohm impedance and another with 34-ohm impedance can be identified.
Advanced Options with HFSS
For more accurate results, use the enterprise license to access HFSS. Define extent regions in SIwave to use HFSS solvers for specific areas, ensuring clean intersections between regions.
Activate the HFSS option in the TDR Wizard to solve specified regions with HFSS instead of SIwave.
Conclusion
The TDR Wizard in SIwave is a powerful tool for analyzing PCB trace impedance and transitions. For more detailed options, review the PI SYZ solver video. SIwave excels in handling large PCBs efficiently, and with HFSS, it can provide even more precise results.
Thank you for watching. We hope you found this video informative.
SI wave is a power integrity and signal integrity tool. In this video, we will be talking about the TDR Wizard and its features, specifically TDR simulation.
TDR is necessary to examine the impedance of the traces in a PCB, detect any discontinuity, and identify issues with any transition, primarily via transitions. TDR is extracted from the S parameters and is considered part of the SYZ or PI solver.
SI wave can do fast but accurate TDR calculations of hundreds of traces in large boards. No other software can beat SI wave in this. It is not recommended to use SI wave to build a PCB. Although one can do that, that is not the right way to utilize SI wave.
SI wave can import IPC 2581, ODB++, DXF, GDS, and ADB files if you have a translator, such as an ANSYS translator in the CAD tool. When you upload any file, SI wave extracts lots of information, including the stackup, the material, the components, and the nets.
To start a process in SI wave, whether it's DC, PI, signal integrity, or radiation, you must select a solver. Once a solver has been selected, SI wave generates a dialog box. The user needs to check the form and fill in the missing information.
To analyze any trace, you must select it and then press add. Each trace must have one TDR probe and one termination. If the trace is a differential line, the user must select the positive and negative TDR probe, as well as the positive and negative termination.
Next, you must specify the signal specifications used in the TDR analysis, including the rising time, pulse width, and pulse period. The pulse width should be set to a longer time, usually longer than twice the trace's length. The pulse period should be set to double the pulse width.
You can also set the delay if needed. In the final step, you define the solver. You can generate a netlist instead of a schematic or select the next option. SI wave will finish doing the S parameter solution of all the traces and then transfer all the data to the electronic desktop.
It will plot the TDR response and the voltage response for you. If you select the second option, SI wave will also generate the schematic for you, which you can use for further TDR analysis or other purposes. The transient simulation is done to derive the TDR.
You must specify the step size and the stop time. The stop time is usually equal to the pulse width. When it comes to the step size, you can select to have 1/5 or 1/10 the rising time. The solver will solve for the S parameters first.
You need to specify the bend, starting from zero and going up to a maximum value. You can add more bends if you want. The minimum rising time is related to the maximum bend value. If you want a minimum rising time of 10 gigahertz, the minimum rising time will change to 50 picoseconds.
If you have an enterprise license, you can specify regions, called extent regions, where you want SI wave to use different kinds of solvers. For example, you can specify a region to be solved using HFSS instead of SI wave.
SI wave and HFSS will cut the region and solve it in HFSS, then later cascade it with the results of SI wave. That's pretty much all there is to the TDR Wizard in SI wave. I hope you enjoyed the video. Thank you.
