EMA Resources

Blog

Home > EMA Resources > Blog > PDN Simulation Optimization

PDN Simulation Optimization

Published: September 22, 2025

Power Distribution Network (PDN) simulation is a critical part of the electronic design process, ensuring reliability, thermal management, and signal integrity. Furthermore, with even smaller devices and ever-increasing design parameters, designers are now facing increasing challenges in maintaining efficient and stable power distribution. Leveraging PDN simulation can significantly aid in the design process, reduce development time, and mitigate risks related to overheating, electromagnetic interference (EMI), and voltage fluctuations.

We’ll also be focusing on Cadence’s Celsius suite. Notably, the Celsius Thermal Solver and Celsius PowerDC which empower designers with integrated electrothermal co-simulation, improving speed, accuracy, and insight.

What is a PDN?

A Power Distribution Network (PDN) encompasses the entire pathway by which electrical energy is delivered from a power supply to the various components within a PCB. This network typically consists of voltage regulators, capacitors, inductors, connectors, planes, vias, and traces. Its primary function is to supply a consistent and stable voltage and current to all the active components on the PCB, ensuring optimal performance and reliability.

Cadence’s PowerDC enables DC voltage and joule-heat co-simulations, identifying IR drop and thermal stresses.

Importance of PDN in Electronic Design

Poorly designed PDNs lead to voltage drops, excessive heat, and signal integrity issues, potentially causing system failures and costly redesigns. PDN issues can manifest in several ways, including:

voltage ripple
transient noise
ground bounce
thermal hotspots

Each adversely affects device functionality and lifespan. Cadence’s Celsius Thermal Solver addresses these issues by simulating steady-state and transient power-induced heating across PCBs and enclosures using highly parallelized FEA and CFD analysis. This ensures:

Reliable power delivery under varying operational conditions.
Minimization of voltage fluctuations and transient spikes.
Improved thermal management and reduced heat dissipation issues.
Enhanced signal integrity, reducing EMI susceptibility.

Leveraging PDN Simulation for Optimal Performance

PDN simulation involves computational modeling to analyze how well a PDN delivers power under various conditions. It allows engineers to predict and optimize the performance of power distribution networks early in the design process. Major simulation types include the following:

Major Types of PDN Simulation
Simulation Type	Description	Benefits
Voltage Drop Analysis	Simulates voltage drop (IR drop) to ensure each component receives adequate voltage. Excessive voltage drop can impair performance or cause failures. Use tools like PowerDC to compute IR-drop and current density. This early detection prevents voltage starvation and identifies routing bottlenecks.	Maintains voltage within acceptable limits, ensuring reliable component performance.
Thermal Management	Addresses thermal issues related to power distribution by simulating thermal maps to identify overheating risks. Designers can simulate thermal scenarios under various loading conditions. The Celsius Thermal Solver uses FEA + CFD for full system thermal models, enabling electrical-thermal co-simulation to visualize hotspots, stress, and warpage at routing, package, and system levels. For realtime design iteration, Celsius Studio adds AI-driven optimization and in-design multiphysics analysis.	Improves thermal dissipation through optimized layouts or cooling measures, enhancing device reliability.
Inductance and Capacitance Optimization	Identifies and quantifies parasitic inductances and capacitances through simulation, which can otherwise degrade PDN performance. Enables optimal placement and selection of passive components (capacitors, inductors).	Minimizes impedance, enhances transient response, and improves overall efficiency.
Noise and EMI Reduction	Simulates noise and electromagnetic interference (EMI) within PDNs, accurately pinpointing potential sources and predicting their impacts. Allows designers to adjust routing, grounding, and shielding methods. Celsius Studio helps evaluate PCB thermal gradients that might affect EMI behavior.	Reduces electromagnetic emissions, improves signal integrity, and ensures regulatory compliance.

Steps to Optimize Your PDN Design Through Simulation

Step	Description	Key Actions / Considerations
1	Define Simulation Objectives	Identify key metrics: voltage ripple, thermal thresholds, impedance targets. Utilizing an advanced platform such as Celsius that can handle integrated electro-thermal co-simulation ensures you can predict voltage ripple, temperature thresholds, and impedance targets under realistic operating conditions.
2	Establish Accurate Simulation Models	Create precise electrical/thermal models using PCB stack-up, component datasheets, and material properties. For DC-level PDN simulation, Celsius PowerDC uses PowerTree source/sink definitions
3	Initial PDN Analysis	Perform baseline simulations; identify hotspots, voltage drops, and impedance issues. Document results. Utilize Celsius Thermal Solver for detailed thermal mapping and joule heating
4	Implement Design Improvements	Adjust trace width, capacitor placement, copper thickness, and component selection based on simulation insights. Prioritize impactful improvements. Leverage Celsius Studio’s AI optimization engine to explore design variations efficiently
5	Re-simulate and Iterate	Run updated simulations, validate improvements, and fine-tune iteratively to optimize PDN performance. The massively parallel solvers in Celsius accelerate this process by up to 10×.
6	Final Validation	Prototype physical boards, validate simulation results through lab testing, and ensure simulated vs. real-world alignment.

Celsius For PDN Design

Cadence’s Celsius Thermal Solver and Celsius PowerDC integrate into PDN design workflows and enable PDN simulation by providing simultaneous electrical and thermal co-simulation.

Celsius enables designers to visualize IR drop and Joule heating concurrently, ensuring accurate identification of thermal hotspots caused by voltage drops. Its scalable simulation capabilities allow quick iterations while maintaining accuracy, helping engineers refine decoupling capacitor placement, copper thickness, and plane structures to achieve optimal thermal and electrical performance.

Additionally, Celsius supports transient thermal analysis and full 3D system-level simulations, enabling engineers to evaluate thermal dissipation strategies and airflow impacts on PDN performance, ensuring reliability and thermal efficiency in high-density designs.

EMA Design Automation is a leading provider of the resources that engineers rely on to accelerate innovation. We provide solutions that include PCB design and analysis packages, custom integration software, engineering expertise, and a comprehensive academy of learning and training materials, which enable you to create more efficiently. For more information on PDN simulation and how we can help you or your team innovate faster, contact us.