Design Smart, Sign Off Smarter: Voltus-XFi for Transistor-Level Power Signoff

25 Jun 2025 • 5 minute read

Imagine you've just built your dream home. You’ve double-checked the plumbing, inspected the wiring, and everything feels perfect. But as you’re about to move in, you find leaks in the plumbing and sparks flying from the wiring. It's a nightmare scenario, right? This is exactly what happens to engineers when they face power integrity issues late in the design cycle. These aren't just backend problems—they're design-time landmines. And with deep submicron nodes, these issues become trickier. Power integrity issues, such as electromigration (EM) and IR drop, can lead to functional failures, reduced product lifespan, and costly redesigns. And that’s where Cadence’s Voltus-XFi comes to the rescue! It is a next-gen transistor-level EM-IR (Electromigration and IR Drop) signoff solution. Designed for SPICE-level accuracy, Voltus-XFi is tightly integrated with the Virtuoso platform, enabling layout engineers and circuit designers to perform fast, accurate, and debug-friendly power integrity analysis.

Why Voltus-XFi?

As semiconductor designs scale in complexity, ensuring power integrity at the transistor level becomes critical. Traditional signoff tools often fall short in accuracy and performance, especially for advanced nodes. Cadence’s Voltus-XFi isn’t just another EM-IR tool. It’s your early-warning system, your simulation powerhouse, and your debug assistant—all rolled into one. For more details, watch this video on
What is Voltus-XFi, and What are its Core Capabilities?

It’s designed for designers who want:

SPICE-level accuracy with Spectre X
Seamless integration with Virtuoso ADE and Quantus
Support for dynamic, static, and SPGS EM-IR analysis
A single cockpit for setup, simulation, and debug
Batch mode and distributed simulation for large designs

In short, it’s the power signoff tool that speaks your language. It isn’t just about passing signoff—it’s about doing it faster, smarter, and with confidence. Whether you’re designing analog IP or SRAMs, Voltus-XFi gives you the tools to:

Catch issues early
Debug efficiently
Sign off with foundry-certified accuracy

For more information, watch this video on Overview of Spectre EM-IR Analyses and Target Applications of Transistor-Level EM-IR Analysis

Walkthrough of EM-IR Signoff Using Voltus-XFi

Let’s walk through a practical scenario where a custom analog design undergoes transistor-level EM-IR (Electromigration and IR-drop) signoff using Voltus-XFi. This example illustrates the complete flow from setup to analysis, highlighting how the tool simplifies and accelerates the process.

Step 1: Design Setup in Virtuoso ADE and Save the EM-IR Setup State

Create a maestro view, configure Spectre X, define corners, and save your EM-IR setup state in the ADE Explorer/Assembler environment.

Step 2: Launch Voltus-XFi and Configure Tungsten View

Create a tungsten view, define project settings, and auto-load EM rules and tech files. You define your power nets, signal nets, extraction settings, and simulation flow—all in one place. Use Quantus to generate a DSPF file. Validate it with the DSPF Linter to ensure simulation readiness.

Step 3: EM-IR Simulation with Spectre X

Link your testbench, choose between direct and iterated solver methods, choose the iterated solver, and apply +emirpreset=mx for balanced accuracy and performance. Generate the EM-IR Configuration file. Run simulations in GUI or batch mode, or distribute across multiple machines for faster turnaround.

Step 4: Analyze EM-IR Results

Load results into the Voltus-XFi Results Browser, docked to the Virtuoso Layout window, to visualize IR drop and EM violations on the layout.

Analyze the Waveform Data results in Virtuoso Visualization and Analysis graph window more information, watch this video on Viewing Waveform Results in Voltus-XFi

Additionally, EM-IR reports are generated and made available in Voltus-XFi tungsten view.

Use advanced IR drop debug techniques like Least Resistive Path (LRP) to trace weak power paths, and Point-to-Point (P2P) analysis to measure resistance between any two nodes, helping you quickly identify and fix layout issues.

Conclusion: Signoff with Confidence

Power integrity issues are silent killers in silicon. With Voltus-XFi, you get a robust, accurate, and efficient solution for transistor-level EM-IR signoff. It’s not just a tool—it’s a definitive power signoff tool that aligns perfectly with your design workflow.

So, the next time you’re staring down a tapeout deadline, remember Voltus-XFi. It's an all-in-one solution that empowers users to navigate complex power integrity analyses confidently and efficiently, ultimately leading to successful design signoff with higher reliability and reduced risk of costly redesigns.

Cadence’s official training on Transistor-Level Power Signoff with Voltus-XFi covers everything from setup to advanced analysis. By the end of the course, you’ll not only understand how to use Voltus-XFi—you’ll be ready to sign off your designs with confidence.

Watch AND Learn: Voltus-XFi Video Tutorials

To further enhance your understanding, here are some valuable resources available on the Cadence ASK - Learning Portal:

and many more videos…

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