The Effects of Variations in Manufacturing on PCB Thermal Properties

2011 ◽  
Author(s):  
John F. Maddox ◽  
Roy W. Knight ◽  
Sushil H. Bhavnani
Keyword(s):  
Thermal Properties ◽  
Steady State ◽  
Thermal Resistance ◽  
Thermal Performance ◽  
Manufacturing Process ◽  
Printed Circuit Board ◽  
Electronic Device ◽  
Circuit Board ◽  
Printed Circuit

The thermal performance of an electronic device is heavily dependent on the properties of the printed circuit board (PCB) to which it is attached. However, even small variations in the process used to fabricate a PCB can have drastic effects on its thermal properties. Therefore, it is necessary to experimentally verify that each stage in the manufacturing process is producing the desired result. Steady state thermal resistance measurements, taken with a comparative cut bar apparatus based on ASTM D 5470-06, were used to compare PCBs manufactured from the same design by different vendors and the effects of vias filled with epoxy versus unfilled vias on the thermal resistance of a PCB. It was found that the thermal resistance of the PCBs varied by as much as 30% between vendors and that the PCBs with epoxy filled vias had a higher thermal resistance than those with unfilled vias, possibly due to the order in which the manufacturing steps were taken.

Evaluation of new technologies and materials for printed circuit boards with improved heat dissipation properties

Circuit World ◽  
2016 ◽  
Vol 42 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Michal Baszynski ◽  
Edward Ramotowski ◽  
Dariusz Ostaszewski ◽  
Tomasz Klej ◽  
Mariusz Wojcik ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Printed Circuit Boards ◽  
Heat Dissipation ◽  
Printed Circuit Board ◽  
New Technologies ◽  
Electronic Device ◽  
Circuit Board ◽  
New Materials ◽  
Content Type ◽  
Printed Circuit

Purpose – The purpose of this paper is to evaluate thermal properties of printed circuit board (PCB) made with use of new materials and technologies. Design/methodology/approach – Four PCBs with the same layout but made with use of different materials and technologies have been investigated using thermal camera to compare their thermal properties. Findings – The results show how important the thermal properties of PCBs are for providing effective heat dissipation, and how a simple alteration to the design can help to improve the thermal performance of electronic device. Proper layout, new materials and technologies of PCB manufacturing can significantly reduce the temperature of electronic components resulting in higher reliability of electronic and power electronic devices. Originality/value – This paper shows the advantages of new technologies and materials in PCB thermal management.

scholarly journals Development of infrared thermal mapping technique for electronic devices

2021 ◽  
Author(s):  
Sanjay Ailani
Keyword(s):  
Steady State ◽  
Transient Analysis ◽  
Printed Circuit Board ◽  
Electronic Device ◽  
Circuit Board ◽  
Experimental Setup ◽  
Test Setup ◽  
Printed Circuit ◽  
Thermal Mapping ◽  
Heat Spreading

The goal of this research project is to develop an experimental setup that is capable of demonstrating thermal behavior of the electronic device. The project focuses on thermal mapping at device, integrated circuit and printed circuit board (PCB) level. A unique technique to perform thermal mapping on integrated circuits and printed circuit board based on Infrared Thermography is proposed in this research project. The developed experimental setup is capable of performing steady state and transient analysis at device and PCB level. The proposed test setup is applied to perform thermal mapping on 68HC11 microcontroller board to predict accurate temperature distribution on the real time operating printed circuit board. The accuracy and validation of the experimental setup are the two major challenges faced in this work. Apart from this, to know the exact transistor junction temperature, it is necessary to develop methodology that prevents heat spreading, allows proper cooling and the one that provides stable cooling thermal coefficient. The performance of infrared thermography has been validated against thermocouple results. The experimental results are compared with the ones obtained by digital thermometer. In order to achieve stability and certainty in the results, insulated environment is preferred. Thermocouple results can be taken as reference since it is in physical contact with the die or the package. Cooling of the electronic device is also performed in this work. Oil based heatsink has been implemented using mineral Aldrich oil which is specially designed for IR spectroscopy. Several different combinations of layers of coating of Boron Nitride spray and black spray paint are deployed with different emissivity settings. The effect of the number of color layer coatings and emissivity values have been investigated. Various challenges pertaining to heat spreading, heat dependent cooling coefficients and spatial resolution have been resolved. The performance of the test setup has been evaluated for both steady state and transient analysis. In additon, thermocouple results have been taken as reference.

An Assessment of the Impact of Interconnect Strategies on Thermal Performance of GaAs Power Amplifier IC Devices

2001 ◽  
Author(s):  
V. H. Adams ◽  
T.-Y. Tom Lee
Keyword(s):  
Thermal Resistance ◽  
Power Amplifier ◽  
Thermal Performance ◽  
Flip Chip ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Printed Circuit ◽  
Wire Bond ◽  
Die Attach ◽  
The Impact

Abstract Alternative interconnect strategies are being considered in place of the standard wire bond interconnect for GaAs power amplifier MMIC devices due to cost and electrical performance improvements. The package/die thermal performance consequences are potentially high-risk issue to these interconnect strategies and requires evaluation. Thermal simulations are conducted to compare and evaluate the thermal performances of three interconnect strategies: wire bond, gold post-flip chip, and through via interconnects. The test vehicle simulated is a three-stage, dual band power amplifier integrated circuit dissipating approximately 5 W steady-state power. Parametric studies are conducted to evaluate the impact of the printed circuit board, die thickness, solid gold vias, and design enhancements on package thermal performance. Best thermal performance is provided by a wire bonded, thin GaAs die attached with solder die attach to a printed circuit board that maximizes the number of plated-through-holes directly under the die. This configuration results in a best case junction-to-heat sink thermal resistance of 12 °C/W. Optimum flip chip and through via designs result in degraded thermal performance compared to the above described wire bond design but may have acceptable thermal performance. For these simulations, predicted junction-to-heatsink thermal resistance is in a range of 15–20 °C/W and is better than a comparable wire bonded design that uses a conductive epoxy die attach material.

scholarly journals Development of infrared thermal mapping technique for electronic devices

2021 ◽  
Author(s):  
Sanjay Ailani
Keyword(s):  
Steady State ◽  
Transient Analysis ◽  
Printed Circuit Board ◽  
Electronic Device ◽  
Circuit Board ◽  
Experimental Setup ◽  
Test Setup ◽  
Printed Circuit ◽  
Thermal Mapping ◽  
Heat Spreading

The goal of this research project is to develop an experimental setup that is capable of demonstrating thermal behavior of the electronic device. The project focuses on thermal mapping at device, integrated circuit and printed circuit board (PCB) level. A unique technique to perform thermal mapping on integrated circuits and printed circuit board based on Infrared Thermography is proposed in this research project. The developed experimental setup is capable of performing steady state and transient analysis at device and PCB level. The proposed test setup is applied to perform thermal mapping on 68HC11 microcontroller board to predict accurate temperature distribution on the real time operating printed circuit board. The accuracy and validation of the experimental setup are the two major challenges faced in this work. Apart from this, to know the exact transistor junction temperature, it is necessary to develop methodology that prevents heat spreading, allows proper cooling and the one that provides stable cooling thermal coefficient. The performance of infrared thermography has been validated against thermocouple results. The experimental results are compared with the ones obtained by digital thermometer. In order to achieve stability and certainty in the results, insulated environment is preferred. Thermocouple results can be taken as reference since it is in physical contact with the die or the package. Cooling of the electronic device is also performed in this work. Oil based heatsink has been implemented using mineral Aldrich oil which is specially designed for IR spectroscopy. Several different combinations of layers of coating of Boron Nitride spray and black spray paint are deployed with different emissivity settings. The effect of the number of color layer coatings and emissivity values have been investigated. Various challenges pertaining to heat spreading, heat dependent cooling coefficients and spatial resolution have been resolved. The performance of the test setup has been evaluated for both steady state and transient analysis. In additon, thermocouple results have been taken as reference.

Thermal Model of Printed Circuit Board Plated-Through Hole under One-Sided Heating Conditions

2021 ◽  
Vol 26 (5) ◽  
pp. 426-431
Author(s):  
V.A. Sergeev ◽  
◽  
A.M. Khodakov ◽  
M.Yu. Salnikov ◽  
◽  
...  
Keyword(s):  
Quality Control ◽  
Thermal Resistance ◽  
Thermal Model ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Thermal Models ◽  
Printed Circuit ◽  
Plated Through Hole ◽  
Through Hole

Thermal methods of quality control of the plated-through hole (PTH) of printed circuit board (PCB) are based on thermal models. However, known thermal models of PTH take no account of heat transfer to PCB material thus not allowing for PTH heat characteristic tying up with adhesion quality. In this work, an axisymmetric thermal model of a single-layer PCB PTH under one-sided heating conditions is considered. It was shown that the ratio of the temperature increments of the upper (heated) and lower end of the PTH in the considered range of heating power does not depend on the power level. A linear thermal equivalent scheme of the PTH has been proposed, which includes the longitudinal thermal resistance of the PTH metallization, de-termined by the parameters and quality of the metallization layer, the thermal resistance, which determines the convection heat exchange between the ends of the PTH with the adjacent PCB surface and the environment, and the thermal resistance of the area of the PCB material adjacent to the PTH, depending on the quality of the metallization adhesion and the PCB dielectric. Thermal equivalent circuit parameters determined by the ratio of the temperature increment of the upper and lower ends of the PTH and their difference can serve as the basis for the development of a nondestructive inspection procedure for PTH quality control by way of its unilateral heating, for example, by a laser beam.

Analysis of surface insulation resistance related failures in electronics by circuit simulation

Circuit World ◽  
2017 ◽  
Vol 43 (2) ◽  
pp. 45-55 ◽  
Author(s):  
Vadimas Verdingovas ◽  
Salil Joshy ◽  
Morten Stendahl Jellesen ◽  
Rajan Ambat
Keyword(s):  
Printed Circuit Board ◽  
Electronic Device ◽  
Early Stage ◽  
Circuit Simulation ◽  
Circuit Board ◽  
Insulation Resistance ◽  
Electronic Circuits ◽  
Content Type ◽  
Printed Circuit ◽  
Surface Insulation Resistance

Purpose The purpose of this study is to show that the humidity levels for surface insulation resistance (SIR)-related failures are dependent on the type of activators used in no-clean flux systems and to demonstrate the possibility of simulating the effects of humidity and contamination on printed circuit board components and sensitive parts if typical SIR data connected to a particular climatic condition are available. This is shown on representative components and typical circuits. Design/methodology/approach A range of SIR values obtained on SIR patterns with 1,476 squares was used as input data for the circuit analysis. The SIR data were compared to the surface resistance values observable on a real device printed circuit board assembly. SIR issues at the component and circuit levels were analysed on the basis of parasitic circuit effects owing to the formation of a water layer as an electrical conduction medium. Findings This paper provides a summary of the effects of contamination with various weak organic acids representing the active components in no-clean solder flux residue, and demonstrates the effect of humidity and contamination on the possible malfunctions and errors in electronic circuits. The effect of contamination and humidity is expressed as drift from the nominal resistance values of the resistors, self-discharge of the capacitors and the errors in the circuits due to parasitic leakage currents (reduction of SIR). Practical/implications The methodology of the analysis of the circuits using a range of empirical leakage resistance values combined with the knowledge of the humidity and contamination profile of the electronics can be used for the robust design of a device, which is also important for electronic products relying on low current consumption for long battery lifetime. Originality/value Examples provide a basic link between the combined effect of humidity and contamination and the performance of electronic circuits. The methodology shown provides the possibility of addressing the climatic reliability of an electronic device at the early stage of device design by using typical SIR data representing the possible climate exposure.

Superconducting Multilayer High-Density Flexible Printed Circuit Board for Very High Thermal Resistance Interconnections

2018 ◽  
Vol 193 (3-4) ◽  
pp. 578-584 ◽  
Author(s):  
Xavier de la Broïse ◽  
Alain Le Coguie ◽  
Jean-Luc Sauvageot ◽  
Claude Pigot ◽  
Xavier Coppolani ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Printed Circuit Board ◽  
High Density ◽  
Circuit Board ◽  
Printed Circuit ◽  
Flexible Printed Circuit ◽  
High Thermal Resistance ◽  
Very High

Surface temperature of electronic assemblies equipped with tilted and low-powered QFN64 subjected to free convection

2017 ◽  
Vol 27 (6) ◽  
pp. 1304-1310 ◽  
Author(s):  
Abderrahmane Baïri ◽  
Clara Ortega Hermoso ◽  
David San Martén Ortega ◽  
Iken Baïri ◽  
Zsolt Peter
Keyword(s):  
Surface Temperature ◽  
Inclination Angle ◽  
Printed Circuit Board ◽  
Electronic Device ◽  
Thermal Design ◽  
Circuit Board ◽  
Content Type ◽  
Printed Circuit ◽  
Volume Method ◽  
Electronic Assemblies

Purpose This work deals with the case of the quad flat non-lead 64 (QFN64) electronic package generating a low power range ranging from 0.01 to 0.1W. It is installed on one side of a printed circuit board (PCB) that can be inclined relative to the horizontal plane with an angle varying between 0° and 90° (horizontal and vertical positions, respectively). The surface temperature of the electronic assembly is subjected to air natural convection. Design/methodology/approach Calculations are done by means of the finite volume method for many configurations obtained by varying the generated power and the inclination angle. Findings The distribution of the surface temperature is determined on all the assembly areas (QFN and PCB). The study shows that the thermal behaviour of the electronic device is influenced by the generated power and the inclination angle. The 3D numerical survey leads to correlations allowing calculation of the average surface temperature in any part of the assembly, according to the power generated by the QFN64 and the inclination angle. Originality/value The proposed accurate correlations are original and unpublished. They optimize the thermal design of the electronic QFN64 package, which is increasingly used in many engineering fields.

Influence of the area of a thermal pad on optical and thermal parameters of LED modules

Circuit World ◽  
2020 ◽  
Vol 46 (2) ◽  
pp. 65-70 ◽  
Author(s):  
Krzysztof Górecki ◽  
Przemysław Piotr Ptak
Keyword(s):  
Thermal Resistance ◽  
Power Density ◽  
Printed Circuit Board ◽  
Thermal Parameters ◽  
Circuit Board ◽  
Optical Parameters ◽  
Metal Core ◽  
Content Type ◽  
Printed Circuit

Purpose The purpose of this paper is to present and discuss the results of measurements illustrating influence of the area of a thermal pad and the kind of the used base on thermal and optical parameters of LED modules. Design/methodology/approach LED modules including six power LEDs are designed. In the layout of these modules, different areas of a thermal pad of each LED are used. These modules are made using the classical FR-4 base and metal core printed circuit board (MCPCB). Thermal and optical parameters of all the tested modules are measured using the method elaborated by the authors. Findings The obtained results of measurements prove that increasing the area of a thermal pad causes a decrease in thermal resistance of the tested LED modules and an increase in power density of the emitted light. The role of the area of a thermal pad is more important for the classical FR-4 base than for MCPCB. Research limitations/implications Investigations were performed for only two values of the area of thermal pads and selected values of LEDs forward current. Originality/value The presented results of investigations show how the used layout and type of the used base of these modules influence optical and thermal parameters of LED modules. Changing the base of a module can cause even a double decrease in thermal resistance and a double increase in power density of the emitted light.

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