Thermal analysis for pcb. Fig. Our engineer will discuss what your objectives are and Ansys thermal analysis solutions help engineers solve the most complex thermal challenges to predict how their designs will perform with temperature changes. The latter might not be as cost-effective. Improve product reliability across environments. As PCB substrates are two dimensional, the thermal conductivity of a finished, unassembled circuit board is best measured using the guarded hot plate method, or the 3-omega method can be used with AN-1520 A Guide to Board Layout for Best Thermal Resistance for Exposed Packages. Mar 4, 2020 · Differential thermal analysis setup (left) and DTA curve (right) The glass transition temperature (Tg) in a PCB substrate or other material can also be identified in a DTA curve as an endothermic phenomenon (i. Active cooling methods include using cooling fans, proper component spacing, and liquid condensation with heat pipes. Thermal relief, also known as thermal break, is an important design consideration for printed circuit boards (PCBs). The most difficult and important step is In this particular case study, the Celsius Thermal Solver successfully performed a complete 3D-IC analysis of a package with multiple chiplets where the complete model, imported in its entirety into Celsius (inclusive of the full substrate model and detailed power maps for the chiplets) consisted of a PCB, a roughly 30x30cm square package, two Jun 1, 2020 · thermal Flow Thermal analysis of a PCB with a chip in Nx Siemens SimCenter tutorial for beginnerIn this tutorial, you will simulate the heat transfer from an . Thermal analysis must be carried out in the concept phase Using PCB Thermal Simulation in the Pre-Development Design Phase. Thermal Simulation Tools and Software. 5 Sep 18, 2020 · The most generic definition for thermal paste is that it is a paste chemically constructed to allow for heat transfer. and here a result of a simulation on a quite complex board. 6 W/mºC. Analyse, calculate, and design the hardware thermal control of a PCB. All boundary conditions and analysis setting are Feb 5, 2021 · In PCB design, effective thermal conductivity is an important aspect used in thermal modelling and analysis because it allows engineers to predict how well a populated PCB would conduct heat based on specific assumptions and models. The thermal conductivity of common PCB substrate materials ranges from 0. Understand the most used cooling techniques and all the parameters influencing it. Thermal analysis is impor Apr 15, 2020 · thickness is 1. The +5 V output from your power supply should remain at +5 V when it reaches VCC pins, and it j-a of an XLamp XQ-D and an XH-G LED, each mounted on a 25 mm X 25 mm FR-4 PCB on a heat sink, as shown in Figure 9. The type of physical change being studied determines the choice of analysis technique, one of which is computational fluid dynamics (CFD Feb 23, 2024 · Feb 23, 2024. Thermal analysis enables engineers to identify regions of poor thermal management. Thermal analysis is printed circuit board design is vital for ensuring desired performance and longevity of your next product. One valuable application of thermal analysis is for the characterization of electronic materials and components, including printed circuit boards (PCB) and encapsulants. Antonio Pio Catalano* 1,2, Ciro Scognamillo 1,2, Roberto Trani, Alberto Castellazzi. Simcenter 3D makes iteration easier by combining multidisciplinary tools in a single environment. One important area where standards have come about, but where the accuracy of the standards is less than desirable, is in defining current limits in PCB traces. This complex 3D computation fluid dynamics software that predicts airflow and heat transfer in and around electronic equipment, including the coupled effects of conduction, convection and radiation. The optimal distance from via-to-via is 0. Sep 25, 2020 · Experimental V alidation of Analytical Models for Through-PCB Therma l Vias. Avoid multiple product prototypes and test failures. PCB designers must consider heat dissipation problems, including the strategic placement of heat sinks, thermal pads, and vias. Account for temperature fluctuations. Temperature cycling is the most common cause of electronic failure. Explore key drivers for faster turnaround time of PCB thermal analysis, from the complexity of modern multi-layer Printed Circuit Board (PCB) designs to the relentless pressure to reduce time-to-market. Understand information about the airflow, temperature distribution, and heat transfer in the PCB layout. 06mm2 compared to 0. The thermal analysis steps are shown in the form of a flow chart in the Fig. Active Cooling Methods. The video contains 3 simu Jan 25, 2021 · Talk to one of our reliability experts to learn more about failure analysis. Product Code: PCB Ver: 5. Figure 4 shows an example of a graph that illustrates the impact of spreading plane area on junction temperature for an example device and PCB stack-ups. PCB Software is a fully integrated analysis package which allows the user to build a printed circuit board visually on the screen or load a previously designed What Is Thermal Analysis. Dec 21, 2023 · The future of thermal analysis in PCB design. There are several methods to model PCBs and the importance of having accuracy in Jun 13, 2020 · PCB Thermal Analysis using Ansys-Icepak. 7 Thermal Shock Testing. Jan 31, 2022 · PCB Thermal Analysis From Stackup to Assembly. Other options include aluminum, chrome, and nickel. A typical PCB tray under study is shown in Fig. The analysis provides designers with an idea of the heat generation and transfer within the circuit. PCB Design Optimization for Thermal Environments. A glass transition will appear in a solid composite/polymeric material (i. Numerical solutions using Galerkin approach that is one of Finite Element Method (FEM) was used to study and analyze the temperature rise on PCB. 3. So, when complex fluid behavior interacts with the heat transfer of a design, SOLIDWORKS Flow is the tool to use. The copper acts as a thermal conductor and the laminate acts as a Electronics Cooling & PCB Thermal Simulation and Analysis. The derivation of the analytical solution is introduced in Section 2. png. 5 to 5 Amperes to capture the Apr 10, 2024 · Watch this video demonstration below to learn how to use the Material Map SmartPart and how to import a Material Map text file into a PCB thermal analysis workflow. Ex Tax: $1,500. It involves creating small gaps in the copper on a PCB around This PCB simulation encompasses PCB thermal design considerations such as the. In addition to those PCB design factors summarized in the preceding section, some other factors involved in packages and boards were also studied using FEA based on the thermal performance of a 28L e- TSSOP package on various PCB boards. Higher accuracy comes with higher computational cost. This test can also signal important transitions in the material structure (glass Apr 15, 2020 · This essay makes the reliable analysis and modelling on printed circuit boards(PCB) by software of Flotherm and get conclusions of three points through simulation analysis:1) there is an important impact on heat transfer of the distribution of copper foil on PCB, and the actual condition should be selected for different precision simulation modules; 2) the heating device with simple structure May 7, 2019 · There are three main steps for setting up a FEM model: Creating/importing geometry. Mar 22, 2021 · A unified PCB design package that integrates advanced PCB design and layout features with a comprehensive substrate material library and production planning features. PCB and TIM thermal resistance are largely dependent on the PCB layout design so R θPCB and R θTIM are of interest for this thermal analysis. November 3rd, 2014. Objective : The main objective of this challenge is to learn the concepts of the PCB modeling and also the How to import trace layout of a typical PCB and solve two sample cases based on the trace layout information. Your Thermal Analysis Report. 8 mm thickness with various trace sizes. They are generally more efficient in heat reduction through conduction and convection mechanisms, but require a power source Mar 13, 2024 · The main results of this paper are as follows, (1) Compared with ANSYS, MFEP takes less time while maintaining calculation accuracy. Register Now. First, the losses of each part of Jan 24, 2020 · Cadence PCB solutions is a complete front to back design tool to enable fast and efficient product creation. thermal analysis of a PCB and the homogeneity approximation has to be verified, which will be discussed in next section. This test is based on similar methodologies as MIL-STD tests for thermal reliability. Easy-to-use with quick actional insights gives you the ability to identify and solve electronics cooling issues early in the design process with ease. Specifically, IPC D coupons are specified to be subjected to thermal shocks ranging from -55 °C to the minimum of: Tg - 10 °C, reflow Dec 6, 2023 · Thermal analysis will check/verify that all hot spots within the design are mitigated and optimized to ensure the best potential for your PCB to perform as intended prior to fabrication. how to model resistive For a 0. When using the Celsius Thermal Solver for PCB and IC Figure 5: EVALSTDRIVE101 second inner-layer PCB Figure 6: EVALSTDRIVE101 bottom-layer PCB To STDRIVE101 In this article, an integrated coreless axial-flux permanent-magnet synchronous machine (AFPMSM) system is integrated with winding and drive/control circuits on a same printed circuit board (PCB) stator. Analysis of non-homogeneity due to tracks and vias The complicated non uniform structure in a PCB is the main difficulty in thermal modeling, because a PCB is usually composed of stacked metal layers and insulating layers. Both address design practices that intend to keep a circuit board operating within some safe temperature range. When viewing the construction PCB thermal analysis refers to the process of establishing the thermal module of components and set simulation control parameters according to the structure and raw material of PCBs, package type of components and PCB operating environment to estimate values of thermal behaviors of PCBs. over 3 years ago. The FVM-based numerical solution was used to analyze heat spreading through tracks and vertical thermal conduction through vias. Vias and proper via management can increase heat How Our Software Helps. All PCBs will generate some amount of heat, but reliability is a matter of determining whether a design will operate as intended during operation despite heat generation. Higher accuracy usually means longer time for the calculations and the modelling. 9:00 am to 4:00 pm PT. Designers can then use analysis results and simulations to come up with techniques that will Ansys thermal analysis solutions help engineers solve the most complex thermal challenges to predict how their designs will perform with temperature changes. Figure 9: XQ-D (left) and XH-G (right) thermal measurement configurations. PCB-Investigator Physics is the perfect tool to simulate the physical behavior of PCBs during the development phase. , before the melting point). here is a demo of the basics. Ensuring thermal reliability requires getting the board temperature as low as possible, which is all about material selection, component layout, and placement of other features like mounting holes and slots. $1,500. By ZM Peterson • Jan 31, 2022. Embracing thermal analysis not only safeguards against potential pitfalls but also lays the groundwork for pioneering advancements in electronic systems. From here, we change the parameters of each PCB element and check changes in the thermal resistance. First, we take out mechanical 3D model of the PCB board May 31, 2022 · Both SOLIDWORKS thermal analysis tools can be used to solve a myriad of problems. Your report can be as simple as an analysis of a single PCB or as complex as an analysis of a complete system, such as a rack-mounted, standard 4U chassis containing up to 18 3U boards. Some of the commonly used software tools for performing PCB thermal analysis are: Thermal analysis must be performed to ensure the plane meets the minimum area required to keep the junction temperature below the absolute maximum temperature. e. Applying boundary conditions. While you can use different diameters for thermal vias, the optimal final diameter for the best thermal conductivity is 0. The most basic approach for dealing with the complex geometry of a PCB is to assume ‘lumped’ or ‘effective’ material properties. simplified as solid block of fixed thermal conductivity;2) Inte rmediate precision modeling: PCB This paper presents a comprehensive thermal analysis of is used for the thermal analysis and the baseline PCB design is illustrated in Fig. August 31st, 2022 - By: Cadence. Your PCB thermal resistance is an important part of heat management. PCB Enclosure structure form design. Because measurements are basically impossible to gather, CFD analysis relies on simulations to evaluate the effectiveness of a cooling strategy. 2(b). Once a board failure occurs, it needs to be investigated and Failure can arise gradually due to accumulated damage (e. Availability: 99999. The two standards covering this area of design are IPC-2152 and IPC-2221. PCB uniformly radiates at 20W / m^2. This PCB thermal analysis calculator is used to estimate the junction temperature rise of an exposed pad device attached to a printed circuit board (PCB). Application Note: Optimizing PCB Thermal Performance for Cree XLampLEDs AN_100302-draft8e. How to use Model layers separately option for better accuracy. The modeling methodology proposed for the thermal analysis of the PCB structure is mainly based on the coupled analytical–numerical solution. The heat spreading through tracks and the vertical heat transfer through vias are taken into account in a numerical way and regarded as the Jan 6, 2022 · PCB Failure Analysis. Cool components in PCB design using a proper approach. Thermal Analysis: Instantly visualize hotspots to prevent overheating, no manual calculations needed. Feb 15, 2022 · Thermal Territories can help you realize appropriate accuracy within the time pressures of your PCB thermal analysis process. FreeCAD forum: FEM simulation results. The video demonstrates how a thermal analysis can be done to a PCB board made of FR-4 which includes 4 memory chips and a CPU chip. 1 PCB modelling There is a trade-off when it comes to thermal analysis of PCBs. All materials are FR4. 5 Space Systems Thermal is used for thermal analysis. Jun 25, 2021 · Hi there! In this video we are going to show how to use SiWave by Ansys to calculate a PCB temperature on different part of the PCB. 2mm, each layer of copper thickness is 1OZ): 1) primary precision modeling: PCB is. The calculator computes the total junction to ambient PCB thermal resistance due to the conduction, convection and radiation. Aug 6, 2019 · To improve heat dissipation, the through-hole contacts should have an increased copper layer thickness. Oct 6, 2019 · Conduct Thermal Analysis. The most typical function for thermal paste is as a filler between two surfaces to provide a solid interface and increase the Jan 6, 2020 · Designing for High Performance PCB Systems. Our PCB thermal simulation analysis program tools include a robust library of models for materials such as alloys, industrial grade polymers, and IC packages just to name a few. g. Temperature profiles, gradients, and excess temperature maps enable designers to resolve board and component overheating early in the design process. Typical CFD analysis workflow for PCB thermal simulation has common stages, such as EDA Sep 16, 2022 · Now, the thermal analysis of the board is performed by using the ANSYS tool, depending upon the results the placement of the components on the PCB is changed and the thermal analysis is performed again until the desired output is achieved. With transient and steady-state simulations, you can quickly evaluate how your cooling Master the reliability aspects of thermal management, cooling and derating, especially with respect to electrical and thermal stress factors. Prevent overheating issues. Read Article. 30 millimeters. 1432×943 192 KB. Optimizing thermal relief and copper pours can help regulate temperature and prevent overheating of components and board IPC-TM-650 2. Jul 12, 2022 · Here's a really basic thermal analysis: thermal distribution 2022-07-13_13-53. Heats of cure. The PCB with four different width of copper is supplied with different range of direct current (DC) from 0. High performance PCB systems design is all about ensuring your PCB meets or beats tolerances in six key areas: Power integrity: You need to ensure stable power with suppressed noise throughout your PCB. 80 mm. 3 to 0. Feb 9, 2018 · Thermal analysis. By proactively addressing thermal concerns during the initial design stages, engineers can optimize system performance and enhance reliability. Conducting thermal analysis using a PCB thermal simulation tool enables designers to do the following: Avoid thermal hotspots and high-temperature affected areas in PCBs at the pre-development stage. Oct 19, 2022 · July 16th, 2024. Some models [1015] are based on analyzing. This is shown in the graphic below. Aug 1, 2014 · 5. We import this model into thermal simulation CAD. , a dip in the DTA curve). Virtual Prototyping: Test and refine your PCBs digitally, slashing the time from concept to validation. For improving the efficiency, the multigrid strategy is integrated in the coupling method for generating discrete cells of three levels in the metal layer and PCB surface region and the model of Taking direct airflow measurements from a PCB during operation is infeasible due the small size of most boards. The impact of heat on PCB performance, reliability, and efficiency is significant, making it necessary to run PCB thermal simulations of design layouts to ensure electronic product designs are optimiz. Analyzing the effective thermal conductivity of a PCB is quite a common method and has been used for deriving the numerical solution or the analytical solution of the thermal distribution in a PCB. May 10, 2015 · The contribution describes effective tools for practical education of PCB thermal analysis. 1432×943 516 KB. For thermal analysis CAD geometry is usually overly detailed. Request Info. 6. The first step in this method includes calculating the orthotropic properties of the glass-fiber reinforced laminate layers. Cyprien Rusu. Meshing the model. Cost-effectively construct the PCB with Aug 1, 2014 · A modeling methodology is proposed for the thermal analysis of the PCB structure based on integrating both the FVM-based numerical solution and the Fourier-series-based analytical solution of temperature. docx. TMA is mostly used to determine the coefficient of thermal expansion ( CTE) before and after Tg of PCB base materials. Proper thermal management is essential for the longevity and reliability of electronic devices. These may be good areas of design iteration and improvement. This is an FEA simulation of a PCB board. This seems reasonable according to one source. 6mm diameter via with 35 m (1 oz. For both cases (i. Electronic components have functional temperature limits, thermal cycling can stress boards and solder joints resulting in fatigue issues and tighter packaging and cost limitations constrain possible countermeasures. PCB thermal analysis strategies focus on understanding how much heat is generated in a PCBA and Nov 3, 2014 · PCB Board Transient Thermal Analysis. 2 W/m/K. The upper temperature in the test is set to be below Tg of the laminate material. Thermal analysis can help address the following key properties of electronic materials: Softening temperature or Tg. R θJC is fixed value that can be obtained from datasheet. ) copper plating, the area (normal to the thermal pad) is only 0. Create a thermal coupling between the chip and the PCB. Performing a thermal analysis establishes how the components and PCB will behave at different temperatures and conditions. Here's what I mean by really basic: Components other than the mosfet are removed to simplify meshing. by easyw-fc » Fri Feb 09, 2018 10:21 pm. Thermal Management is vital for electronics durability and performance. Active methods are often used for microprocessors or high-power output designs. Thermal analysis of the PCB is conducted by computing the This paper presents the analysis of temperature rise on PCB. 3) The coefficient of thermal expansion of the PCB board is 0, so only the copper chips expand, causing outward forces at the top surface of the board, which explains why it curves upward. 1. Designed with Electronics and Electronics Systems Cooling in Mind. 2. Three broad areas of product reliability – electrical, thermal and mechanical reliability – require evaluation to produce reliable PCB designs with a long service life and reduced product failures. So the first step is to simplify geometry or create new geometry. Demonstration samples were created for practical exercises in the area of simulation and measurement of temperature fields on surface of PCBs. HyperLynx Thermal allows engineers and PCB designers to analyze board-level thermal problems on placed, partially routed, or fully routed PCB designs from all popular PCB layout environments. – effective isotropic conductivity or layer-wise effective conductivities. 0. PCB layout board structure. Understanding thermal management techniques and thermal vias in PCB is essential to minimize heating issues and boost thermal performance. We measured and simulated FR-4 PCBs of 0. The thermal conductivity of copper is about 400 W/m/K and the thermal conductivity of FR-4 is 0. Thermal stress analysis results help PCB designers build reliable, robust, and optimized multilayer PCBs. Four different design Mar 22, 2021 · The thermal conductance is easily calculated from the thermal conductivity, and the thermal resistance is the inverse of the thermal conductance. This is much lower than the accepted thermal conductivity of copper (386 W/mºC). 3% of the original Apr 5, 2022 · The most commonly used conductive material is copper. With electronic modules continuing to shrink in size, it is a parameter that deserves attention amongst designers. Insights into operating temperatures based on design decisions. , Vincenzo d’Alessandro 1. Note: This video above also reviews 2R component thermal modeling approaches. Video: Exploring Simcenter Flotherm XT 2021. Many of our customers are reaping the benefits of the trace import functionality in Ansys Mechanical, which accounts for the effects of copper distribution on every layer of a printed circuit board (PCB) — or printed circuit board assembled (PBA) — for your thermal Jun 6, 2019 · Product thermal failures and significant late-stage design rework due to prototype thermal testing are costly issues that prove the value of learning and app Feb 12, 2018 · Most FEM packages would crash, but CCX is very forgiving. steam, water, oil). Aug 1, 2014 · Improved Numerical-Analytical Thermal Modeling Method of the PCB With Considering Radiation Heat Transfer and Calculation of Components’ Temperature. The starting geometry is provided as well as the FreeCAD macros which reproduce the steps to set up the examples. 28mm2 for a solid via, resulting in a thermal resistance of 441 C/W per. By combining finite element analysis (FEA) for solid structures with computational fluid dynamics (CFD) for fluids, the Celsius Thermal Solver enables complete system analysis in a single tool. 00. The CFD tool in SOLIDWORKS Flow can find the heat transfer rates and coefficient that the FEA tool (Simulation) requires as user inputs. It is typically caused by a coefficient of thermal expansion (CTE) mismatch between the PCB components and the board. Nov 11, 2016 · Importing ECAD Trace Data for Better Thermal and Vibrational Analysis. the FVM-based numerical solution and the Fourier -series-based analytical solution of Thermal reliability encompasses multiple aspects of your PCB, including substrate materials, material interfaces, and components. The convection coefficient strongly depends on the medium (e. Thermal stress analysis can detect stress affected areas in a circuit board Printed circuit boards (PCBs) are present in all electronic devices and are the core elements responsible for the device functioning properly. , fatigue), erratically (random or intermittent), or sudden (due to shocks). (2) In this paper, the thermal layout optimization method of PCB power devices based on MFEP and genetic algorithm is verified by ANSYS simulation, which can reduce the maximum junction temperature of MOSFETs on PCB by about 19 ℃, to 83. Nov 16, 2022 · PCB Thermal Analysis . TSurface. Thermal analysis is an analytical technique whereby changes in the physical state of a substance or its products are evaluated as a function of temperature and time (in some cases). A complete analysis of your design can be done to any extent you require. Its composition is a liquid polymer, that may include urethanes, acrylates, silicones and epoxies. Convection describes the mechanism of heat exchange between an external face of a solid body and the surrounding fluid such as air, steam, water, oil, etc. Determining the limits of PCB reliability is all about pinpointing failures, as well as how they arise in the device. Automate PCB thermal analysis to shorten development. XQ measured Chart. This application note provides some key points on how to reduce thermal resistance in designing the PCB. Evaluating thermal performance impact of PCB construction variations between 2-layer, 4-layer, 6-layer, etc. In this way, thermal hotspots, critical line resistances and excessive voltage drops can be identified, found and remedied even before the first prototype! With the built-in editing functions of PCB-Investigator Physics, it is A thermal coupling models conduction between the entities of components that are physically or thermally in contact. 4) In the Simscale analysis the authors apply heat sources at all chips on the board and show the May 22, 2021 · Thermomechanical Analysis (TMA) is a thermal analysis method in which linear dimensional change is measured as a function of temperature. 2 Thermal Territories and EDA Bridge enhancements. The appropriate tools are focused on demonstration of thermal dissipation possibilities and thermal interactions between power components and on practical Sep 29, 2018 · Commercial software NX 8. Jun 25, 2020 · Method 1: Lumped or Effective Material Properties. 2. Package selection. Tags: Software , Thermal Analysis , Fluid Flow , Transient , steady state , 3d Modeling , KCR Software. The losses and thermal problems of winding and drive/control circuits are very important for the safe operation of the integrated PCB coreless AFPMSM system. In the event that your printed circuit Aug 29, 2016 · Using kicad StepUp for the conversion from the board and the MCAD model to be analyzed, FreeCAD development release now can do a thermomechanical analysis on kicad pcb boards…. Aug 31, 2022 · In-Design Thermal Analysis For MMIC And RF PCB Power Applications. Next-generation wireless communication and radar systems often demand increased RF power within a smaller footprint to meet the performance and size requirements of their respective important component in these analysis. The most typical function for thermal paste is as a filler between two Mar 22, 2021 · The materials used in your stackup will help determine the overall thermal resistance and resulting heat transfer rate in your board. Analysis of buried copper planes and effectiveness of thermal vias in transferring heat between layers. Aug 1, 2014 · A modeling methodology is proposed for the thermal ana lysis of the PCB structure based on integrating both. Example test problems consisting of slides to walk you through the set-up process. This presentation outlines a workflow between Ansys Sherlock, Ansys Icepak, Ansys SIwave, and Ansys Mechanical that combines simulations with - PCB thermal resistance; • R θTIM - TIM thermal resistance, and • R θHSA - heatsink-to-ambient thermal resistance. 1. Efficient Design Optimization: Use precise simulations to streamline designs, reducing material and space requirements. Conclusions. Feb 14, 2022 · In designing PCBs, thermal effects must be considered. Then, an algorithm has been developed using MATLAB. Cadence enables users accurately shorten design cycles to hand off to manufacturing through modern, IPC-2581 industry standard. The non-conductive substrate most commonly used is FR-4 laminate. The measured value of each thermal resistance is listed for a 1-, 2-, or 4-layer PCB that complies with the JEDEC standard JESD51. PCB modelled into actual ten layers and two layers), the mechanical tray is modelled with structured hexahedral grid and the same tray is used for both cases. Celsius EC provides a comprehensive thermal analysis toolset purpose built for electronics. For maximum accuracy a fine resolution of the PCB is needed to match the accuracy of the detailed semiconductor package model to accurately capture the connection between the package and the copper traces. Mar 28, 2022 · What is the basic introduction of PCB thermal paste? The most generic definition for thermal paste is that it is a paste chemically constructed to allow for heat transfer. Ansys Icepak provides powerful electronic cooling solutions that utilize the industry leading Ansys Fluent computational fluid dynamics (CFD) solver for thermal and fluid flow analyses of integrated circuits (ICs), packages, printed circuit boards (PCBs) and electronic assemblies. 1 Thermal Simulation 3D PCB Assembly. Modern electronics use high-power components like high-performance processors, MOSFETs, high-power LEDs, IGBTs, etc. pp ek tc tv lz xd nq qx az jy