Using imported detailed PCB designs and IC thermal properties to speed up thermal analysis
Benefits
Save time and effort by using imported detailed PCB designs and IC thermal properties for analysis;
Quickly import detailed PCB data into Simcenter FLOEFD;
Improve analysis accuracy with more detailed thermal modeling of electronics.
EDA Bridge
Simcenter FLOEFD's EDA Bridge module provides capabilities for detailed import of printed circuit boards (PCBs) into the mechanical computer-aided design (MCAD) tool of your choice in preparation for thermal analysis. Historically, the best way to access PCB data was to use Intermediate Data Format (IDF) file pairs, which present several problems, especially regarding the geometry of the copper on the PCB.
The Simcenter FLOEFD EDA Bridge allows detailed import of PCB thermal properties of materials and integrated circuits (IC) into Simcenter FLOEFD for thermal analysis on its own or as part of a larger system-level assembly.
PCB Import File Formats
Simcenter FLOEFD EDA Bridge can use four file formats for import:
IDF
CC and CCE (native file format for Xpedition™ software and PADS™ software from Siemens Digital Industries Software)
ODB++ (neutral file format for PCB manufacturing)
IPC2581B (IPC Digital Product Model neutral file format)
The benefit of using CCE, ODB++ or IPC2581B is the PCB stackup and copper geometry can be read and used to create 3D geometry.
This is particularly useful when thermal considerations, such as vertical connection thermal access (vias) or copper leaks, have been designed into the board.
PCB Modeling Levels
A PCB can be modeled in four ways using Simcenter FLOEFD: compact, layered, explicit or using the new Smart PCB. The most appropriate approach depends on the required granularity of the thermal simulation, evaluated against the time available for analysis in a design and the constraints of the EDA data available at the design stage.
More information about each approach:
1. Compact: An orthotropic material property is created to account for in-plane and direct-plane thermal conductivities based on the copper content within the board.
2. Layered (detailed): Each layer has its own material property based on the copper coating of the layer, including dielectric layers with vias. PCB material thermal conductivity modeling options for compact and layered approaches:
Analytics: A well-known legacy approach where effective properties are determined based on the volume average of copper and dielectric of individual layers of the board or the entire board.
Empirical: a unique and patented approach where effective properties are based on a percentage correlation of coverage with the explicit representation of copper. Several validation examples have shown that results based on empirical effective thermal conductivities more accurately predict component temperatures than the analytical method.
Empirical effective in-plane conductivity
3. Explicit: Explicit copper modeling can be performed at more mature design stages when fully routed board information is available. You can import CCE, ODB++ or IPC-2581B files that contain the board netlist and copper layout, and then all the appropriate 3D geometry will be created. Alternatively, you can adopt the subset approach to model individual networks for Joule Heating analysis using the explicit network approach: Specific networks can be selected and modeled as explicit. The software will then create 3D geometry to resemble the entire network, including vias, in Simcenter FLOEFD.
4. Smart PCB: a new approach where the copper and dielectric within a routed board are represented using a lattice assembly. For a fully routed board, this is a very computationally efficient method for faster solution time. The fidelity of the representation can be adjusted by switching between fine, which guarantees two network assemblies in the width of the smallest stroke, or medium, which allows full control to coarsen or refine the network assembly.
SmartPCB is a unique approach to PCB ECAD data processing that enables thermal, thermoelectric and structural simulation. The number of cells in the CFD mesh and the time to solve SmartPCB are much smaller than a fully explicit approach, but maintain the same amount of detail. To understand the Fine Resolution approach and, more generally, SmartPCB creation, consider each layer represented by an equivalent image of the copper distribution. The maximum resolution that can be achieved is 1 pixel, on the order of 10 microns. Cells or blocks in larger areas of Copper or FR4 are merged to reduce the number of nodes in the network representation.
Thermal Territories – Localized PCB Modeling Fidelity
Improved localized modeling fidelity definition supports faster, more computationally efficient PCB thermal analysis. It eliminates the need to explicitly model the entire PCB, without sacrificing accuracy where it is needed most. To accurately account for the influences of layer complexity and copper trace where they are most critical, users can select an area under a critical component (a standard thermal territory) or define an arbitrarily defined rectangular area anywhere on the PCB to cover the properties of the board under a group of components (autonomous thermal territory). Multiple thermal territories can be defined on a single board and defined as compact, layered (verbose), or explicit type in conjunction with how the board's overall thermal modeling level has been defined.
IC Modeling
IC components or packages can be thermally represented in several ways to simulate electronics cooling.
Within EDA Bridge you can configure the following models during import. If component heights are not defined in the electronic design automation (EDA) tool, a default can be specified in the EDA Bridge:
Simple: use block representations of the components. The size is based on the contour of the assembly or placement with the defined material properties.
Two resistors: use Joint Electron Device Engineering Council (JEDEC) thermal resistances θJB and θJC.
DELPHI Multi-Resistor: Advanced thermal resistance network compliant with JEDEC guidelines with additional network nodes imported as a network assembly.
Detailed models represent all 3D materials and geometry of a component.
Note: Detailed models based on clean 3D CAD geometry can be generated using the Simcenter FLOEFD Package Creator application in minutes.
PDML Import
PDML was originally a Simcenter Flotherm™ software format often used by vendors to provide users with an IC package simulation model. This IC package definition in *.pdml format can be imported into Simcenter FLOEFD and contains information about the geometry, energy load, material properties or the thermal compact model definition and radiative properties of the surface.
Electronic component filtering
ICs, resistors, and other components can be filtered based on one or more criteria. This is designed to allow users to remove thermally insignificant components from the analysis to speed up computational time. The mounting holes can also be filtered.
Users can filter parts based on: footprint dimension, height, power, power density, or reference designator.
Import power list
A CSV file containing the datum designator and a number can be used to apply multiple boundary conditions in one operation, rather than part by part. This feature is useful when many components are present. A CSV file can be exported for further use or editing if necessary.
Possible imported boundary conditions range from the type and modeling properties of the IC to its dissipated power.
PCB electrothermal co-simulation
Using the Smart PCB generated in EDA Bridge and transferred to Simcenter Flotherm to model a board as a network assembly, users can set up a co-simulation with HyperLynx™ PI DC drop analysis software. This co-simulation more accurately represents the power dissipation of the board's copper trace by modeling changes in electrical resistance versus temperature. It is configured in the PCB property sheet and the user selects the appropriate networks to model.
At each iteration in the co-simulation, the temperature results are passed to a DC drop analysis to better model the changes in copper's electrical resistance with temperature and then an updated joule heating power map of the grid. Electrical PCB is fed into system-level thermal analysis for accuracy and temperature prediction and so on. It is also possible to control the frequency with which thermal information is passed between the two tools, defining the periodicity of the co-simulation. Overall, this electrothermal modeling solution allows engineers to better predict temperature influences more accurately and then identify areas of excessive voltage drop and high current density that can cause malfunctions.
FloEFD: An Integrated Thermal Analysis Solution
With Simcenter FloEFD , engineers can perform thermal analyzes directly in the CAD environment, leveraging data imported by EDA Bridge. This integration eliminates the need for additional simulation software, simplifying the design workflow.
Interface FloEFD
Combining FloEFD with the EDA Bridge module enables more accurate and detailed thermal analysis, optimizing PCB design for better performance and reliability. FloEFD's electrothermal co-simulation provides in-depth insight into thermal and electrical interactions, resulting in more robust and efficient designs.
Schedule a meeting with the experts at CAEXPERTS today and take your PCB thermal analysis to the next level! Save time and effort with detailed import of PCB designs and IC thermal properties into Simcenter FLOEFD. Enjoy the benefits of faster, more accurate thermal modeling, ensuring more efficient electronics designs. Don't miss the opportunity to improve your thermal analysis - schedule your meeting now with CAEXPERTS!