Integrated Signal and Power Integrity Analysis FAQs

August 27, 2025

General

1. What features are included in the professional version of OrCAD X 24.1?

Everything demonstrated is available in OrCAD X Professional or higher. We also demonstrated the new Sigrity X Aurora integration that will be released as part of OrCAD X 25.1 in September 2025.

2. We have an Allegro Venture License, and we just use the regular Allegro. Do we need a separate license for the new OrCAD X PCB Layout?

If you have Allegro X PCB Editor, you don’t need OrCAD X PCB Layout. Sigrity X Aurora is integrated into both the classic PCB editor and the new OrCAD X PCB Layout. Also, the new OrCAD X PCB layout will be included with Allegro X in the 25.1 release coming in September 2025.

3. Is the new OrCAD X PCB Layout interface the only user interface for new product versions? Are we going to completely lose the classic PCB editor interface?

No—both interfaces are supported. The new PCB layout interface is geared to EEs, new designers, or PCB layout engineers focused on medium to low-complexity designs. The classic PCB interface is the expert layout environment, and both interfaces support Sigrity X Aurora.

4. Where can we find a quick demo on topology extraction and simulation?

You can learn more about Topology Explorer and how to use integrated analysis to determine and verify constraints for high-speed parallel bus interfaces by watching this video.

5. Is the IR Drop Workflow included in the standard OrCAD X Pro package?

Coupling and cross-talk workflows are included with OrCAD X Pro and Allegro X Designer. The other simulation workflows, like IR drop, require a Sigrity X Aurora license.

Sigrity X Aurora

6. How do you enable the Sigrity analysis workflows in the classic PCB editor? And is it available in previous releases like 23.1?

You need a Sigrity X Aurora license. OrCAD X already has crosstalk and impedance, and the other workflows will only be available in 25.1 (September release) or higher. In Allegro X, Sigrity X Aurora integration has been available in PCB Editor for years and is currently available in Allegro X 23.1.

7. I'm using Allegro X Venture with PCB Productivity Toolbox. Do I need to install Sigrity X Aurora as well?

With Allegro X Venture, you have access to all the Sigrity X analysis workflows. An additional license is not required, but you are required to install Sigrity X Aurora to allow the analysis to run.

8. Can you explain more about Sigrity X licensing in terms of the different types and how to get it?

Please contact your local reseller, Cadence Account manager, or Cadence sales if you’re new to Cadence, to discuss the licensing options for Sigrity Aurora X.

9. Does OrCAD X require similar parameters setup like Sigrity X Aurora for analysis?

Yes, since this is Sigrity X Aurora integrated with OrCAD X PCB layout, the setup requirements are the same.

10. Could you demo analyzing Eye diagram?

Eye diagram analysis is part of the full-blown Sigrity X System SI and not part of in-design analysis. Watch this video for more information.

11. Did Cadence discontinue SigXplorer? It seems like Cadence is trying to replace SigXplorer/SigWave with Topology Extraction.

Yes, SigXplorer is an old technology that has since been replaced with Sigrity X Topology Explorer.

12. How do you generate PowerTree?

PowerTree is included with Sigrity X and can generate and manipulate power rails defined in schematic, PCB, or package.

13. We often get the feedback that min/max scale values cannot be adjusted. Say there is very high impedance of 150 Ohms, this value determines red color. The problem is that other values, such as 50, 60, 70 ohms almost appear with the same color, making the review difficult. The point tools have such capability. Are there plans for improvement?

Yes, there are roadmap plans to add and enhance measurement techniques in Sigrity X Aurora.

14. For coupling calculations, do you consider E-Field or H-Field?

No, not in Aurora. However, our Sigrity sign off tools take into consideration both E and H fields. The coupling workflow in Aurora is just a graphical parallelism report.

15. Could you use this tool to inform capacitor values choices for noisy power supply mitigation?

Yes. There is a decoupling capacitor wizard that is part of the full Sigrity Optimize PI solution.

Technical

16. How do you resolve issues related to coupling?

Coupling problems vary, and how you resolve them is specific to the problem. In-design analysis expedites the identification of those problems so you can modify the layout and then rerun analysis to see if the fixes you applied work. We have additional workflows besides crosstalk that can help you quickly identify victim aggressor scenarios this will help you hone in on actual problem areas.

17. What is the maximum current density acceptable for external and internal layer?

The industry reference is IPC-2221/IPC-2152, which provides empirical charts and equations for allowable current as a function of copper thickness, trace width, and acceptable temperature rise.

18. Is the coupling coefficient check applied to traces on the same layer only, or is it also applied to traces on adjacent layers?

Coupling coefficient is a calculated value based upon a physical distance in 3D from victim to all aggressors or individual aggressors.

19. It looks like the demo is all in viewer mode. Is it possible to do it in Allegro viewer?

The demo is being conducted with OrCAD X Professional. Simulation data and overlays are not currently available in the viewer but are coming soon.

20. For the Coupling analysis, do you always assume that there is a GND plane underneath the traces (regardless of the actual PCB design) or do you consider the real GND plane design (that may or may not be under or above the traces under study)?

Coupling analysis does not look at ground planes or return path, however crosstalk analysis looks at whatever reference planes are available.

21. If an impedance-controlled trace has a target impedance of 100 but the impedance of this trace is 90ohms on the inner layer, is it acceptable? Or will it cause reflections at high speed? The trace starts and terminates with a 100-ohm trace, but in between the layers, it is 90 ohms. How much impact does it have?

Good question, it really depends on a number of factors. Amplitude or voltage swing of signals in question and how much tolerance can a particular channel support. We would need much more detail to answer this accurately.

22. Is there a full tutorial on how to use the new editor and how it maps to the classic Allegro?

Documentation for the new OrCAD X PCB editor can be found in Cadence online support and on the Cadence PCB and Analysis resource hub. The new PCB interface will be available in Allegro X this September 2025 as part of the 25.1 release.

23. Does the impedance workflow consider traces of solder mask openings?

No, not unless you define the soldermask in the stackup as a conductive layer.

24. What do you suggest for layout designers to learn how to do an IR drop when they might not have a circuit theory background knowledge?

There are several educational resources online that cover power design and DC drop. The beauty of the IR drop workflow is there is not much you have to learn. Run the simulation and look for red areas that require further inspection, make adjustments and rerun the simulation to see the results real-time.

25. Are these workflows only available in the Presto editor or can they be used in the PCB Editor tool as well?

Sigrity X Aurora is currently available in Allegro X in the classic PCB editor. The new OrCAD X and Allegro X PCB layout will be supported in the 25.1 release – scheduled for September 2025.

26. What is the difference between crosstalk and coupling analysis?

Coupling is a percentage of potential coupling for victim verse aggressor. Crosstalk is a simulated value of noise on a victim from different aggressors.