Celsius Thermal Solver - Recent Threads

Importing Icepak model into Celsius EC

NS1170 — Mon, 29 Jun 2026 17:51:01 GMT

Celsius EC Solver can import Icepak models upto V14.5 or earlier. To import the model, click on Import and select TZR.

The models after V14.5 are encrypted and cannot be imported in Celsius EC directly. To import Icepak model, it is recommended to export the model as ECXML file.

ECXML is neutral format thermal model that can be imported in Celsius EC. To import ECXML file, go to Import ribbon and click ECXML to import an ECXML file into Celsius EC Solver as a new model, a component or an assembly.

Multiple Celisus tools

TT202605198653 — Fri, 19 Jun 2026 09:38:08 GMT

When you launch Celsius Studio, there are 5 different tools. What's the purpose of each of them?

We value your Input – Help us bridge Forum Content Gaps

Renu Vibha — Wed, 25 Jun 2025 10:17:34 GMT

Hello Community Members,

We truly value your partnership and the unique perspectives you bring to Cadence Community Forums. As part of our ongoing commitment to improving the community experience, we’re looking to enhance the content available to you.

We would greatly appreciate if you could take a few minutes to participate in our poll and provide details on the specific flow and functionality where content is required as a reply to this thread.

Your feedback is essential in helping us identify opportunities for growth and ensuring the platform continues to meet your needs and expectations.

Thank you in advance for your time, input and continued support.

[Please visit the site to access the poll]

How to build a graphite sheet model in EC (6sigmaET)

HC202506028620 — Mon, 23 Jun 2025 01:10:01 GMT

We use lots of graphite sheets in mobile devices to spread hot spot, as known as the material is thin (0.1mm), and the orthogonal thermal conductivity at different axis.

how to setup the model and grid control to perform the spreading effect and least grid numbers?

What’s new in Cadence®︎ Celsius™︎ Studio - #3

SimTech — Fri, 11 Apr 2025 11:56:07 GMT

This 3-part series highlights new and enhanced features of Cadence^® Celsius^TM Studio in the System Analysis 2024.1 release. The Sigrity and System Analysis (SIGRITY/SYSANLS) 2024.1 HF2 release is now available at Cadence Downloads.

Power Auxiliary Variable

An auxiliary variable, Store Cell Power, has been added to Solution Control. When selected, two new plot types, Cell Power and Cell Power Density, are available to be plotted on a result plane.

Overlapping Power Sources

Celsius EC Solver now supports overlapping sources of power in Subcomponents, Solid Obstructions, and Heat Sources, allowing for a more accurate calculation of power distribution over these objects.

For more details on what’s new in Cadence® Celsius Studio, click here.

Team SimTech

Cadence Design Systems

What’s new in Cadence®︎ Celsius™︎ Studio - #2

SimTech — Sat, 15 Mar 2025 08:13:41 GMT

Terminal Design Using Area-Based Power Maps

In solid extraction flow, you can import area-based power map files to create terminals. For designs with multiple blocks, this capability lets you import an existing power map file instead of manually creating and setting up 2D sheets individually.

Batch Renaming of Parts

For ease of organization, Celsius 3D Workbench lets you rename multiple design parts simultaneously. This is specially useful for complex designs that require managing a large number of parts within an assembly.

For more details on what’s new in Cadence® Celsius^TM Studio, click here.

Team SimTech

Cadence Design Systems

What’s new in Cadence®︎ Celsius™︎ Studio - #1

SimTech — Wed, 26 Feb 2025 09:10:29 GMT

Celsius Interchange Model Introduced

Celsius Studio now supports Celsius Interchange Model generation, which is a 3D model derived from detailed physical designs for multi-physics and multi-scale analysis. This Celsius Interchange Model file (.cim) serves as a design information carrier across Celsius Studio tools, enabling a variety of simulation and analysis tasks.

Optimality Intelligent System Explorer Improved

The Monte Carlo Method GUI in the Optimality Intelligent System Explorer has a separate Monte Carlo Parameter Table to select the parameters that need to be studied. The sampling methods available for Monte Carlo Method are Latin Hypercube and Low-Discrepancy Sequence.

Additionally, defining the objective function is now optional for sweep studies.

For more details on what’s new in Cadence® Celsius™ Studio, click here.

Team SimTech

Cadence Design Systems

Thermal Warpage Simulation in Celsius

SimTech — Thu, 30 Jan 2025 13:19:28 GMT

There has been great deal of interest in electronic design automation(EDA) in electronics industry due to the huge potential on the next generation technologies such as 5th generation(5G) mobile network, high performance computing, autonomous vehicle, meta universe. All these applications required a powerful semiconductor device as their computational unit. For a much higher computing performance, besides the circuit design, the temperature field induced by the circuit power, or the thermal stress analysis during manufacturing process, become more and more important due to the geometry and performance requirement.

A reliable numerical tool, then plays an important role at the early stage of electronic design. An accurate, faithful prediction and evaluation of the design with appropriate numerical modeling can help designer foresee possible issues and save much more development cost. As the Moore’s law stated, semiconductor process technology has been increased in complexity but decreased in size. The limiting space of the device makes the thermal diffusion and stress deformation of each component be the critical issues. The deformation of the component in tiny space will cause huge deflection and undesired conditions of the circuit. Therefore, a numerical tool that focusing on thermal and stress analysis is needed.

Moreover, during stress analysis, the tool should contain several features according to the industrial needs. First, the thermal expansion should be taken into account, as well as the deformation due to thermal expansion mismatch. Next, the temperature dependent material properties should be considered. Some common components such as underfill, epoxy, have glass transition at specific range of temperature, such that the mechanical properties change significantly near this range. This highly temperature dependent characteristics is usually used to reduce the deformation or warpage due to coefficient of temperature expansion (CTE) mismatch between essential components.

Cadence Celsius Thermal Solver, is the product that provided a solution on multi-physics simulation at system level with performing both thermal and stress analysis. To validate the solver, several cases with analytical solutions and shadow Moire experimental measurement from literature are used to make comparison with numerical simulation result, demonstrating the capability of Cadence Celsius Thermal Solver.

To study more about Thermal Warpage Simulation, click here.

Team SimTech

Cadence Design Systems

Running a Sweeping Simulation in Celsius Thermal Solver

SimTech — Thu, 12 Dec 2024 07:34:20 GMT

Once you have set the parameters in the Sweep Analyzer, perform the following steps to run a sweeping simulation:

Click the Start Sweeping Simulation icon in the toolbar. Alternatively, select Simulation — Operation — Start Sweeping Simulation from the menu bar.

The Simulation Confirmation window displays. Click OK to close the window and start the simulation.

The progress of the simulation is displayed in the Output pane.

Note: To stop the sweeping simulation, click the Stop Sweeping Simulation icon in the toolbar. Or, select Simulation — Operation — Stop Sweeping Simulation from the menu bar.

After the simulation run, a directory named Sweeping is created under the current working directory with a separate case folder for each case run. Each of these case folders contain their own .3dth, .tcl, and result files.

For more details on simulation, refer to Celsius Thermal Solver User Guide.

Team SimTech

Cadence Design Systems

DELPHI modelling in Celsius Thermal Solver

SimTech — Tue, 29 Oct 2024 11:40:21 GMT

In DELPHI modeling, you specify parameters for the DELPHI thermal model network of the component, and the tool will model the heat transfer inside the component according to these thermal parameters.

Following steps will help you implement DELPHI model for static analysis:

Right-click the design canvas in the Layoutpane and choose Select > Solids from the context menu.

2. Click to select the object to which you want to apply the component thermal model and right-click and choose Component Thermal Model> DELPHI Model from the context menu.

The Static DELPHI Model window displays.

To add internal nodes for the DELPHI model, right-click in the Internal Nodes canvas area and select Add from the context menu.

Specify a Name and Power (W) value for the node and click OK.

To add external nodes for the DELPHI model, right-click in the External Nodes area and select Add from the context menu.

Select the external node type from the Name dropdown list. This selection defines how the external node corresponds to the physical areas on the actual package. Now, specify a Power (W) and Area (mm²) value of the external node and click OK.

After you have added internal and external nodes, add network connections between these nodes. To do this, right-click in the Network Connection area of the Static DELPHI modelwindow and select Add from the context menu.

Select the nodes to be connected from the Node1 and Node2 dropdown lists and specify the thermal resistance between these nodes in the Resistance (C/W) field. Click OK.

Click OK to close the Static DELPHI Model The DELPHI model is added to the Project pane and its properties appear in the Property pane as shown below.

These steps show how to model a DELPHI thermal model in Celsius. For more information on DELPHI modelling, you can refer here .

Team SimTech

Cadence Design Systems

Computation of Equivalent Thermal Conductivities of Multiple Regions

SimTech — Fri, 04 Oct 2024 10:39:36 GMT

Most other thermal simulation tools cannot model board or package designs layer by layer. For these thermal simulation tools, only one equivalent layer with equivalent thermal conductivities in x-, y-, and z-directions is used to represent all layers.

Following steps describe how to compute the equivalent thermal conductivities of multiple rectangular regions in a board or package design.

1. To start the computation, select Tools > Effective Thermal Conductivity Calculator.

2. In the Effective Thermal Conductivity Calculator pane, right-click and choose Add from the context menu to add a new region.

3. Edit the region size and number of subdivisions in the region.

4. After you have added and defined the region, highlight the region and click Calculate. The computed Kx, Ky, and Kz are displayed on the right, as shown below:

Team SimTech

Cadence Design Systems

Importing Materials library in Celsius 3D

SimTech — Fri, 13 Sep 2024 10:14:20 GMT

Cadence provides a library of materials in an xml (.cmx format) file that is used across various SIGRITY tools. The material library, by default, lists 134 materials.

For more information on the material library file, refer to the Material Library File Reference Guide

To import materials from the material library:

Choose Tools — Edit Library — Material.

In the Material Manager window, select the Show Material Library check box. The Material Manager window expands to show the materials in the material library under the From Library area

Note: When importing materials from a simplified model file, if the imported .xml file is encrypted, all materials in the imported file will be encrypted as well.

To sort the materials by material name or their usage status, click the up or down arrows next to the Name or In Use columns.

Click Export to Design to import the material properties from the material library into the design.

Note: You can click Export to Library to export custom materials to the material library.

Click OK.

Note: If your design contains materials that are not available in the design library, during simulation Celsius will look for materials with same name in the material library and copy them to the design library for running the simulation.

SimTech

Cadence Design Systems

Importing Power Map in Celsius Thermal Solver

SimTech — Mon, 26 Aug 2024 15:21:46 GMT

In Celsius Thermal Solver, instead of specifying the power dissipation values for the tiles, you can also import an existing 2D power map file. To do so, click Import Powermap, navigate to the location of the desired file and click Open.

The grid table and the Layout pane are updated with the power values specified in the imported power map file, as shown below:

Note: In the area-based power map file, apart from specifying the values for lowerleft corner (<llx> and <lly>) and upper-right corner (<urx> and <ury>) for the area, you can specify the total power DIE_TOTAL_POWER for the area. If you specify DIE_TOTAL_POWER in the power map file, the remaining power, after assigning the power to all the blocks, will be evenly distributed to the rest of area.

For more details on importing power map, refer to Celsius Thermal Solver User Guide.

Team SimTech

Cadence Design Systems

Understanding PCB/PKG Thermal Simulation workflow in Celsius Layered Structures

SimTech — Wed, 31 Jul 2024 15:28:15 GMT

PCB/PKG Static Thermal Simulation: This workflow enables engineers to perform static thermal simulation. This workflow combines both electrical and thermal analyses together. Combining electrical and thermal analyses will consider and include both electrical and thermal parameters together, and this leads to highly accurate simulation results. The simulation results include plots for all electrical aspects such as voltage distribution, current density, power density, power loss, IR drop, and via current. Thermal results include plots for temperature rise, heat flux, conductivity, fusion current density, and mean time between failures. You can explore and understand the simulation results in three different ways:

Table View: View both electrical and thermal results in the form of tables. Tables include electrical parameters such as VRM and sink voltages, power loss, global via current, specific via tables, and thermal parameters such as dissipation (case top, case side), PCB dissipation, junction (°C), via, plane, wirebond temperature tables, and so on.
2D Distributions: 2D distribution helps you understand both electrical and thermal results in 2D plots. This includes electrical distribution plots such as voltage, IR drop, current, current density, power density, power loss, fusion current density, and mean time to failure (MTTF). This also includes thermal distribution plots such as temperature, heat flux, and conductivity plots.
3D Distributions: 3D distribution allows you to view the results in 3D color-coded way. Electrical, via, temperature, and heat flux results can be seen here. It allows you to understand the results in a much more realistic way by enabling specific components, animations, 3D structures, and slicing the planes (X,Y,Z).

PCB/PKG Transient Thermal Simulation: Transient simulation is a highly useful capability of Celsius Thermal Solver. Transient simulation allows you to define transient heat sources which can vary over time. You can get the same type of simulation results (as mentioned above), including all electrical and thermal results. Modern systems require transient analysis to study the electrical and thermal distribution over time. This workflow evaluates how the electrical and thermal parameters evolve at different points in the system over a specified period. Transient analysis plays a major role in thermal sign-off by validating the complete design and checking the reliability, efficiency, and performance.

Team SimTech

Cadence Design Systems

What's New in Celsius Studio Systems Analysis 2024.0

SimTech — Mon, 22 Jul 2024 09:23:18 GMT

Cadence Celsius Studio, industry’s first complete AI-enabled multi-physics analysis platform for electronic systems has been introduced in this release. This innovative platform delivers unparalleled capabilities in electro-thermal simulation, warpage and stress evaluation, electronics cooling, and thermal network extraction and simulation. It enables electrical and mechanical/thermal engineers to conduct analysis within a unified platform without the need for geometry simplification, manipulation, or translation. Celsius Studio leverages generative AI optimization through Cadence Optimality Intelligent System Explorer to rapidly explore the design space and converge on the optimal design.

The suite of products within Celsius Studio enables seamless integration of ECAD and MCAD design files, streamlining workflows and facilitating rapid in-design analysis.

Celsius Layout: Facilitates IR-drop, thermal, and warpage/stress analyses, along with electro-thermal and stress co-simulations of layered structure designs, such as PKGs and PCBs with multiple layers and interconnect vias. It also supports thermal model extraction for use in thermal network simulation and leverages Optimality Intelligent System Explorer—an (AI)- driven multidisciplinary analysis and optimization (MDAO) technology—for rapid design optimization.
Celsius 3D Workbench: Enables IR-drop, thermal, and warpage/stress analyses, along with electro-thermal and stress co-simulations of 3D structure designs. It also supports thermal model extraction for use in thermal network simulation and leverages Optimality Intelligent System Explorer— an (AI)- driven multidisciplinary analysis and optimization (MDAO) technology—for rapid design optimization.
Celsius 3DIC: Supports the creation of customized 3D-IC designs in schematic view or the import of designs from the Integrity 3D-IC Platform. It provides comprehensive thermal analysis, as well as warpage and stress analysis capabilities for complex 3D-ICs and structures.
Celsius Electronics Cooling: Addresses challenging thermal/electronics cooling management problems with speed and precision. Celsius Electronic Cooling leverages a powerful computational engine and meshing technology to effectively model and analyze complex designs.
Celsius Thermal Network: Enables the simulation of thermal networks using thermal models extracted from the Celsius Layout and Celsius 3D Workbench tools. It is particularly useful for conducting macroscopic analysis, system-level calculations, thermal characterization, model calibration, and sensitivity analysis.

For more details, click here.

How to Solve a Thermal Challenge in a PCB Using Celsius

SimTech — Thu, 09 May 2024 11:07:36 GMT

Celsius has several solvers, including FEA and CFD. Celsius Layered Structures (2.5D FEA) particularly stands out as an ideal platform for quick thermal simulations that let users create a 3D thermal model via wizards and templates without thermal expertise.

The RAK available on support.cadence.com demonstrate a thermal analysis methodology of solving a thermal challenge in a PCB using Celsius FEA and CFD Technology of Cadence. The RAK cover the thermal analysis process that PCB designers or PCB SI/PI engineers can utilize in Celsius 2.5D FEA to come up with a cooling mechanism for PCBs. Then, the same users or the thermal engineers can do a final signoff of an actual design using Celsius CFD simulation. The workflow of Celsius 2.5D FEA-CFD is used in this RAK, letting users do a trade study of cooling the PCB quickly in 2.5D FEA and run an actual CFD simulation, including a chassis and a fan, in the CFD environment.

The Celsius 2.5D FEA-CFD Workflow Diagram:

SimTech

Cadence Design Systems

Voltus – Celsius Static Electrical Thermal Analysis

SimTech — Thu, 11 Apr 2024 14:22:36 GMT

To run chip or IC thermal simulation, you can use the Celsius Thermal Solver in conjunction with the Voltus^™ IC Power Integrity solution to do electrical and thermal analysis. Below flow shows flow for static (steady-state) electrical-thermal co-simulations for solid objects with layered structures or ICs.

To use the Voltus-Celsius thermal analysis flow, you can do the following:

Generate Voltus ‘Thermal Model’ to be consumed by Celsius.
Generate Celsius ‘Thermal Map’ to be consumed by Voltus.
Analyze ‘Power and EM/IR’ using Voltus applying Celsius thermal map.

The following flow diagram shows the information exchange between Voltus (Chip Power Sign-off tool) and Celsius Thermal Solver:

You can use this RAK to understand about the flow more in detail.

Team SimTech

Cadence Design Systems

Parameterizing your design in Celsius

SimTech — Thu, 14 Mar 2024 11:32:35 GMT

Celsius allows user to run parametric studies on your design to see how it behaves at different variable values. Instead of simulating the design multiple times using different values, you can set sweep parameters for the geometries, materials, or boundary conditions in the design, and the tool will automatically create multiple cases and run sweep simulation for the generated cases.

The boundary conditions that support parameterization are: Static Power and Temperature, Heat Transfer Coefficient (HTC), and VRM/Sink Patch.

Celsius Thermal Solver User Guide mentions the steps for defining sweep parameters for geometries, boundary conditions, and material properties.

What’s new in Celsius Thermal Solver 2023.1 HF2 - #2

SimTech — Thu, 15 Feb 2024 15:15:42 GMT

This 2-part series highlights new and enhanced features of Cadence^® Celsius^TM Thermal Solver in the System Analysis 2023.1 HF2 release. The Sigrity and System Analysis (SIGRITY/SYSANLS) 2023.1 HF2 release is now available at Cadence Downloads.

Bulk Edit Heat Transfer Conditions

By using the new Bulk Edit option in the Heat Transfer Coefficient dialog box of Celsius Solid Objects Simulation for 3D Structures (Celsius 3D) module, you can edit the heat transfer coefficients and temperature values in bulk.

When you specify new values for h(W/(m^2*k )) and T(C), the updated datasets get uniformly applied to the selected rows.

Support for PWL Waveform File in Sink Current

You can now import current values from a PWL waveform file while specifying transient current source for a sink in the Celsius Solid Objects Simulation for 3D Structures (Celsius 3D) module. Use the Import PWL button to import historical current values and perform comparative analysis.

For more details on latest release check out the link.

Team SimTech

Cadence Design Systems

What’s new in Celsius Thermal Solver 2023.1 HF2 - #1

SimTech — Thu, 08 Feb 2024 09:36:48 GMT

Support for Temperature-Dependent Resistors

The Celsius Solid Objects Simulation for Layered Structures (Celsius 2D) module now supports temperature-dependent resistors. A new column, Temp-Resistance Table, has been added in the Voltage Drop Analysis Setup -> Set up Discretes form. You can upload a text file containing temperature-resistance pairs in the Temp-Resistance Table column. This allows you to test a wide range of temperature-resistance data.

If you upload a file with temperature-resistance values, it will override the default resistance.

New Component Filtering Option

Filter by Thermal dialog box in the Celsius Solid Objects Simulation for Layered Structures (Celsius 2D) module now has a new Thickness option that allows you to filter components by their thickness.

Team SimTech

Cadence Design Systems

Simplifying Solid Model Files for Fluid Flow Simulation

SimTech — Thu, 30 Nov 2023 08:04:47 GMT

The original solid models may contain elements that are not critical for fluid simulations. While it is a good idea to keep as much detail as possible for solid simulations, doing the same in fluid simulations may increase the complexity of the mesh. Therefore, it is important that solid components in the model are simplified for achieving faster and accurate simulations.

The following simplified solid types are available in Celsius Fluid Flow Simulation: Mold, LidAdhesive, Lid, HeatSink, PCB/PackageAdhesive, PCB, Package/Substrate, LeadFrame, DieAdhesive, Die, Cooling Duct, Component, Non Rectangular Object, Other, and Mesh Region.

During object simplification, all solid types, except Non Rectangular Object, convert the object to a cuboid. Non-rectangular objects on the other hand, increase the amount of detail while retaining a Cartesian object shape.

Apart from object simplification, simplifying solid models also helps in handling overlapping geometries by setting object priorities. Except for Other, object priority of overlapping geometries increases down the list. In areas where the geometries overlap, objects having higher priorities take precedence over objects with lower priorities.

Team SimTech,

Cadence Design Systems

Type of analysis possible in Solid objects simulation for 3D structures

SimTech — Thu, 09 Nov 2023 12:26:04 GMT

To simulate your design using the static or transient analysis approach:

Choose Simulation – Options

The Option window displays.

2. Click Simulations Options in the Options window to display the simulation analysis options in the right pane.

Note: In the simulation type area, the Static Analysis option is selected by default.

❑ To perform only thermal analysis, select the Thermal option.

❑ To perform electrical and thermal co-simulation, select both Thermal and Electric for static analysis or the E/T Co-Simulation for Transient analysis option.

❑ To perform warpage and residual stress analysis, select the Warpage and Stress option.

If you want to study the thermal behavior of your design when coupled with other factors like electrical and warpage stress, select the Electric or Warpage and Stress check boxes. You can select a combination of these check boxes to study the interaction between thermal, electrical, and structural aspects of your design. However, combining electrical and warpage stress analysis is not allowed.

Regards,

SimTech

Let’s explore various workflows available in Celsius Layered structures

SimTech — Thu, 05 Oct 2023 07:16:48 GMT

The Solid Objects Simulation for Layered Structures module offers the following workflows:

PCB/PKG Static Thermal Simulation
PCB/PKG Transient Thermal Simulation
Chip Thermal Simulation
Package Thermal Characterization
Multi-Board/Package E/T Co-Simulation

The workflow you select should be based on whether you want to perform static/transient simulation of your PCB/PKG design, analyze the chip thermal based on the chip power maps provided by Voltus, thermal characterization, or multi-board E/T co-simulation.

Layout Workbench enables you to switch modes to access different workflows related to

Celsius. To switch modes, perform the following steps:

Select Switch Workflow from the File menu. The Switch Workflow dialog box displays.

2. Select the required workflow on the right pane.

3. Click OK. The related workflow opens in Layout Workbench.

Do let us know in below comments which workflow do you use

Regards,

Team Simtech

Creating Power tree from ODB++ file

Nikita Zapesotskiy — Thu, 07 Sep 2023 15:14:59 GMT

Hi.

I am trying to perform a E/T simulation with Celsius Thermal Solver for layout from ODB++ file.

I follow the workflow but I got stuck trying to create Power Tree.

Power supply connection made by two press-fit connectors PF1 and PF6 for positive and negative power supply pins respectively.

I select the corresponding net to define a starting components, Selecting the positive pin to be PF1 and Negative Pin PF6.

Then I define the trough components but in the end I can't see the PF6 defined as sink on the Power Tree.

What can cause this kind of issue?

Thank you.

Best regards,

Nikita Zapesotskiy.

Editing fan curve in Celsius

SimTech — Mon, 21 Aug 2023 10:58:28 GMT

After you have added a fan or fan tray to your model, you can edit its fan curve. To do so:

In the Project pane, double-click CFD Component.
Double-click Cooling to view the list of fans added to the model. Select the fan for which you want to edit the fan curve.

In the Property pane, click on the browse button next to the fan curve. Alternatively, choose Simulation > Edit Fan Curve.

The dialog box to edit the fan curve for the fan displays.

To add flow rate and pressure data for each point, right-click under the Flow Rate and Pressure Difference fields and select Add from the context menu.

After you have added the fan curve data, click Refresh to plot the fan curve data on the right.

To edit the curve properties, such as curve color, pattern, style, and width, right-click the curve and select Property from the context menu.

Now, specify new properties in the Curve Pattern Property window.

Click Export to export the fan curve data to a .csv file. You can also import the existing fan curve data from a .csv file by clicking Import.
Click OK.

Team SimTech

Cadence Design Systems