Johannes Adam

ADAM Research

What would be a good drill hole diameter so that a given electric current would not overheat (Joule heating) and lead to mechanical damages in the PCB? To get answers, experiments are needed. This note is based on the experimental results of D. Brooks and presents explanations derived from our numerical simulation results. In opposition to general...

Wie warm ein Bauteil oder eine Leiterbahn in einer Baugruppe wird hängt nicht nur von der Verlustleistung ab. Ebenso sind die Grundfläche (foot print), die Wärmeableitung durch Wärmespreizung in Kupfer und FR4, andere Wärmequellen und letztlich die Wärmeabgabe an die Umgebung maßgeblich an der erreichten Temperatur beteiligt. In diesem Magazinbei...

Das Buch ist aus einer langjährigen Durchführung des Seminars «Elektronikkühlung in Leiterplattendesign und -fertigung» des Fachverbands Elektronik Design (FED e.V., Berlin) entstanden. Es will eine gravierende Lücke in der Ausbildung von Elektronik-Entwicklern und -Konstrukteuren füllen, da dort thermische Probleme nur sehr kurz und oberflächlich...

ne of the most interesting findings in IPC 2152, compared to the earlier charts, is that internal traces are cooler that external ones for the same size and current. In the earlier charts, independent experimentation was not done on internal traces. Internal traces were just assumed to be hotter than external traces, and the external trace data wer...

Through the years there has been very little written about the current carrying capacity of a via. This is, I believe, because there has been no practical way to measure or to predict the temperature of a via. We have blindly assumed that it is the current through the via that determines the via temperature, and approached board designs accordingly...

Fans are common helpers for cooling electronic devices. But it's like a zoo. There are big and small, strong and weak, fast and slow. The fan laws (or affinity curves) combine, among other things, diameter D, volume flow G, static pressure P and speed N of propeller fans. A search on the Internet provides you with a large number of hits (e.g. [1])....

The authors have collaborated over the past 18 months on printed circuit board (PCB) heating and cooling issues.1 They have used a computer simulation modeling tool, TRM in many of their studies. As a result, they have been able to identify the major parameters responsible for trace heating and cooling, and have been able to quantify the effects of...

There is not that much material public available comprising a consistent set of fabrication data and experimental results from which thermal electronic board (PCB) models can be built and compared. In a recent article Intersil’s J.Johnston described the thermal behavior of a QFN package on a 4-layer evaluation board based on the vertical thermal re...

Dear Reader, the article is not printable. Please have a look online: https://pcdandf.com/pcdesign/index.php/magazine/10338-thermal-management-1510

Dear Reader, find the articles here: https://www.pcdandf.com/pcdesign/index.php/editorial/menu-features/10546-thermal-overload-1601 https://www.pcdandf.com/pcdesign/index.php/editorial/menu-features/10293-pcb-design-1509

Manchmal interessiert den Baugruppenentwickler nicht so sehr der Beharrungszustand der Bauteil- oder Baugruppentemperatur, sondern der zeitliche Ablauf: zum Beispiel der Aufheizvorgang bis eine Grenztemperatur erreicht ist oder die Peakwerte in einer Pulsfolge.

In Teil 3 geht es darum, was man bei der Dimensionierung von Leiterbahnen aus Sicht ihrer Strombelastbarkeit beachten muss.

In Teil 2 wird gezeigt, dass das Layout bzw. die Kupferlandschaft um eine Wärmequelle entscheidend zu Form und Ausdehnung der Wärmespreizung beitragen und damit die Wärmeabfuhr beeinflussen.

Einführung und Wärmeübergang

Leiterplatten im Automotive-Bereich und in der Leistungselektronik müssen hohe Ströme transportieren, wobei die Temperatur einen Schwellenwert nicht überschreiten darf. Die genauere Betrachtung von Schaltungen auf Multilay-erboards führt aber schnell zu einer komplexen dreidimensionalen Stromheizung und zu entsprechenden Wechselwir-kungen im Wärmet...

A three-dimensional, spatially detailed and combined simulation of electrical current and temperature in PCBs is the best approach to answer the question: “what is the maximum current for a trace at given temperature?” Board layout based on design rules IPC-2221 or IPC-2152 is merely a rough estimate leading to oversized traces or too conservative...

Eine Leiterplatte (printed circuit board, PCB) ist, vereinfacht gesagt, ein mit Hilfe von Kunstharz verpresstes Laminat aus kupferbeschichteten Kunststoffplatten. Das Leiterbild auf den einzelnen Lagen wird dabei photochemisch durch Ätzung erzeugt. Die Temperaturbeständigkeit einer Leiterplatte ist allerdings beschränkt. Beim Standardmaterial FR4 (...

This is a translation to English of the German original conference paper "Die Leiterplatte als Kühlkörper". The scope is to give a higher level introduction to heat spreading and temperature prediction. We make a tour from 0-dimensional to 2D axisymmetric analysis. Why did we bother so much? Mainly for educative reasons: • There is more mathematics...

The widely used design rule IPC-2221 (=MIL-STD-275) for the 'current carrying capacity' of traces on printed circuit boards is subject of a closer investigation. These historical studies on correlations between electrical current and temperature rise of the trace can be reproduced by numerical heat transfer simulations, but only if the board has a...

Im weiteren fokussieren wir uns auf Fragen der lüftergetriebenen Kühlung von Geräten. Anhand von numerischen Simulationen mit dem o.g. Berechnungspro-gramm erhalten wir qualitative und quantitative Lösungen.

Inhalt: Grundlagen und Auswahl von Lüftern und Ventilatoren / Lüftermotoren / Temperatur- und Strömungssimulation im Entwicklungsprozess

The widely used design rule IPC-2221 (=MIL-STD-275) for the 'current carrying capacity' of traces on printed circuit boards is subject of a closer investigation. These historical studies on correlations between electrical current and temperature rise of the trace can be reproduced by numerical heat transfer simulations only if the board has a back...

Fließt Strom durch eine Leiterbahn, so heizt sie sich wegen des Ohmschen Widerstands auf. Gewisse Grenztemperaturen, z.B. die Glastemperatur von FR4, dürfen aber nicht überschritten werden. Die am meisten verwendeten Korrelationen zwischen der Stromstärke auf einer Leiterbahn und der sich durch die Stromheizung ergebenden Temperatur der Leiterbahn...

Strong sd-p2 interaction in the 3d5(4s4d+4p2) complex of doubly excited configurations in Fe II causes a significant mixing and perturbation of sextet levels. This expected strong interaction induces a spin-orbit mixing between a 6D and an 8P term, manifested in an anomalous fine structure. A theoretical treatment of this complex explains the anoma...

http://www.electronics-cooling.com/1998/05/pressure-drop-coefficients-for-thin-perforated-plates/

Die numerische Simulation des gekoppelten Temperatur-Strömungs-Problems in elektronischen Geräten hat sich zu einem wichtigen Aspekt in der elektromechanischen Konstruktion entwickelt. Mit Hilfe feiner Modellierung auf dem Rechner, dem Computer-Aided-Engineering, läßt sich das Wärmeverhalten präzise vorhersagen.

A finite volume method is applied to the three-dimensional radiative line transfer in accretion disks. The two-level-atom approximation with complete redistribution is used. It is assumed that the disks are homogeneous in temperature and pressure. Monochromatic images of the intensity distribution on the surface of disks are given for several assum...

Models for disks around white dwarfs are calculated for two different assumptions on the viscosity parameter alpha(tau). The first one states that alpha should be constant and larger than 0 for all optical depths tau, even in the optically thin photosphere. This leads to the formation of a corona. The second one states that alpha is constant, large...

We apply a finite difference method to the 3D radiative line transfer in accretion disks. The two-level-atom approximation with complete re-distribution is used. As a first step we assume disks which are homogeneous in temperature and pressure. We give monochromatic images of the intensity distribution on the surface of CV disks for several assumpt...

Heidelberg, Univ., Diss., 1989 (Nicht f.d. Austausch).

Detailed geometrically thin alpha-disc models are constructed and their spatially resolved emerging line spectrum is calculated by solving the equation of radiative transport along a large number of lines of sight. Application to the Halpha emission of the cataclysmic system Z Cha shows that - in contrast to black body or model atmosphere approache...

The fractionation problem of minerals in a turbulent protosolar disk is extended to a non-constant grain size due to evaporation and recondensation. Numerical and approximate analytical solutions are given.

Gray models for accretion disks with self-consistent radiation fields are constructed. High-temperature coronae are found to lead to emission components in the lines of hydrogen and helium. The gray radiative transfer problem in an accretion disk is solved self-consistently from first principles. The temperature distribution in the disk is derived,...

The majority of about 120 ultraviolet iron lines, among them strong lines around 1850 Å, which have recently been identified as transitions from doubly excited levels in Fe II during a new investigation of the hollow-cathode spectrum of iron, coincide with absorption lines in the high-resolution IUE spectrum of the sharp-lined A star 21 Pegasi. Mod...

During a new investigation of the UV hollow-cathode spectrum of iron, some 120 lines were identified, among them strong lines around 1850 A, as transitions from doubly excited levels in Fe II. A combination of selective population by charge-transfer processes in the laboratory source and of a strong configuration interaction is probably the cause o...

The relation between the period and magnitude changes of Delta Cephei stars is studied by analyzing the relation between the period and the Fourier series coefficients of the magnitude changes. It is shown that light curves compressed by a constant factor obtain a form quite similar to that of color curves. Because of the similarity, only light cur...