An Electromechanical Approach to a Printed Circuit ... - IEEE Xplore

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IEEE TRANSACTIONS ON EDUCATION, VOL. 56, NO. 4, NOVEMBER 2013

An Electromechanical Approach to a Printed Circuit Board Design Course Danijel Danković, Member, IEEE, Ljubomir Vračar, Member, IEEE, Aneta Prijić, Member, IEEE, and Zoran Prijić, Member, IEEE

Abstract—This paper describes a printed circuit board (PCB) design course based on electromechanical workflow. The course relies on the premise that a PCB is an integral component of any electronic apparatus, along with its other electromechanical and mechanical components. To emphasize this to students, electrical and mechanical computer-aided design tools are used in synergy. The course content is described in detail, and the design workflow is illustrated, using a project to design a data acquisition instrument as an example. Index Terms—3-D modeling, electrical computer-aided design (ECAD), mechanical computer-aided design (MCAD), printed circuit board (PCB) design.

I. INTRODUCTION

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RINTED circuit board (PCB) design is a necessary step in the development of most modern electronic products. Although this was once treated as a mere skill, and often neglected in favor of theoretical subjects, it now features in many academic curricula; as a result of the decrease in component dimensions and the increase in design complexity and working frequencies, the printed circuit board has become a part that can significantly affect overall product performance [1]–[4]. A conventional approach to a PCB design course is to focus the course content on the production technology, the association between the schematics and the board (i.e., components and footprints), board layout, design rules, and routing. Important electrical structures such as split planes and transmission lines are considered, as are, to some extent, electromechanical devices associated directly with the PCB, such as board edge and board-to-board connectors. Electromechanical and mechanical components such as panel-mounted devices, wires, harnesses, enclosures, and racks are often ignored—a legacy of the conventional partitioning between the electrical and mechanical lines of a product design workflow. PCB designers may easily overlook mechanical pitfalls; the consequence can be that several design iterations are required to accommodate the design to the Manuscript received May 21, 2012; revised August 10, 2012, January 18, 2013; accepted March 15, 2013. Date of publication April 24, 2013; date of current version October 28, 2013. This work was supported in part by the Serbian Ministry of Education and Science under Grant TR32026 and the Ei PCB Factory, Niš, Serbia. The authors are with the Faculty of Electronic Engineering, University of Niš, Aleksandra Medvedeva 14, 18000 Niš, Serbia (e-mail: [email protected]; [email protected]; aneta. [email protected]; [email protected]). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TE.2013.2257784

real constraints. This often becomes a cumbersome time-consuming procedure. Companies, of whatever size, could derive substantial benefit from their engineers having already acquired knowledge of the electromechanical design workflow during their university training [5]. Large corporations, especially those in the consumer electronics market, allocate human and financial resources to both the electrical and mechanical design lines; the mechanical line is typically enhanced with industrial designers responsible for the aesthetics and ergonomics of the final product, and for the electrical line, the electrical engineers are given additional highly specialized and expensive training in PCB and electromechanical design. Even though medium-size commercial and industrial electronics companies often largely base their products on standardized mechanical parts available from external suppliers, their personnel still need specialized knowledge. Small and startup companies usually cannot afford this investment in specialization, so may resort to a trial-and-error approach to design that can also prove expensive in the long run. This paper presents a PCB design course for undergraduate students. The key idea behind the course is that the PCB should be viewed as a part of the assembled electronic apparatus, consisting of various electromechanical and mechanical devices. This is elaborated on in Section II along with the course objectives, syllabus, and the adopted collaboration principle between the electrical and mechanical computer-aided design (ECAD and MCAD) tools. Section III describes how the design workflow is implemented in practice in a project to build a microcontroller-based data acquisition instrument. Assessment is discussed in Section IV, and conclusions are drawn in Section V. II. COURSE CONTENT AND DESCRIPTION The course is offered in the winter semester of the third year of a five-year undergraduate degree program in Electronic Devices and Microsystems. Prerequisite courses are Introductory Circuit Analysis, Electronic Devices, Electronic Materials, Signals and Systems, and Microelectronics Circuits. The main course learning objectives are that students: • are familiar with the PCB production process; • understand PCB design principles; • are able to use ECAD and MCAD tools; • are able to design low-density two- and four-layer PCBs; • are able to use ECAD-MCAD collaboration; • are able to understand the overall product design process. The course consists of presenting the ECAD and MCAD design lines and their interaction in the product development workflow, as can be seen in the course syllabus, shown

0018-9359 © 2013 IEEE

DANKOVIĆ et al.: ELECTROMECHANICAL APPROACH TO PCB DESIGN COURSE

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Fig. 2. Interaction between PCB and mechanical CAD tools.

Fig. 1. Product level design hierarchy.

TABLE I SYLLABUS OF THE PCB DESIGN COURSE

in Table I. The course also prepares students for the core fourth-year curriculum courses Microwave Electronics and Microsystems Design, which use PCBs in practical exercises that accompany their theoretical topics. The electromechanical approach is introduced by using threedimensional (3-D) modeling. The product is described as an assembly of parts, with each part having a 3-D model, as illustrated in Fig. 1. The enclosure and fasteners are purely mechanical parts, while the rest are of mixed type, i.e., electromechanical. The printed circuit board is a subassembly consisting of the board itself and the placed components. Each component is fully defined in electrical and mechanical terms by using its schematic symbol, associated footprint, and a 3-D model. Panel devices represent a set of controls and indicators (switches, displays, etc.) that are physically connected to the PCB by cables and harnesses. Modern ECAD tools are software suites, often based on schematic capture used for circuit simulation and PCB layout and routing [6]–[8]. This course focuses only on the PCB

design since students are introduced to circuit simulation in other courses. Three-dimensional component models are introduced into the PCB design either by using built-in creation capabilities of the CAD tools or by importing them from external sources [7]–[9]. A PCB CAD tool having both capabilities [7] was chosen for the course. Many component manufacturers, in particular those producing sockets and connectors, provide 3-D models of their products in formats ready to be used with PCB design and MCAD tools. Therefore, the course begins by presenting the method to create the PCB component, as defined in Fig. 1, using a prebuilt manufacturer-supplied 3-D model. This is followed by an introduction to the procedures for creating a 3-D model of the component in the MCAD tool, using the manufacturer’s technical drawings. The MCAD tool [10] used in the course was selected for its availability in a fully functional free academic version, although other popular tools [11], [12] are available. The synergistic use of ECAD-MCAD is bidirectional, as shown in Fig. 2. First, to define components, component models (either prebuilt or created in the MCAD tool) are imported into the PCB CAD tool. The PCB is then designed using the layout and routing tools according to the specified design rules. Once the board has been completed, it can be exported, along with the components, as a single 3-D model. The common IDF [13], [14] or STEP [15] data formats can be used for this, although more specialized technologies have been developed [16], [17]. The created PCB 3-D model is imported into the MCAD tool where, as depicted in Fig. 2, the product is assembled using other parts. The STEP format is used for the data exchange between CAD tools in both directions in order to maintain consistency. The 3-D model of the enclosure and other devices can be imported into an ECAD tool. However, today’s ECAD tools are much less flexible than MCAD tools in assembly techniques, and they also lack harnessing capabilities. Additionally, MCAD tools are more suitable for advanced simulations such as thermal flow and are widely used in the design of mechatronic systems [18]. The MCAD tool also provides a multi-CAD environment, giving students experience of its use in product data management [19], [20]. The course curriculum consists of 2 h per week for each of the lectures from Table I and another 2 h per week of laboratory exercises and homework assignments. The presentation methodology is based mainly on the direct use of ECAD and MCAD

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Fig. 5. Arrangement and positions of the connectors on the rear side of the enclosure.

Fig. 3. Exploded view of the plastic enclosure used for the PCB definition.

Fig. 6. TO-220 case with heatsink mounted: (left) footprint and (right) 3-D model as defined in the PCB CAD tool. MH1 and MH2 are heatsink mounting holes on the PCB.

Fig. 4. Layout of the various rooms of a sample PCB design.

tools, with slides only being used to clarify PCB technology and design concepts. III. DESIGN WORKFLOW EXAMPLE The course material is presented in the form of a project whose goal is to design a simple data acquisition instrument. The instrument has to acquire data from an external sensor, process them using a microcontroller, and display output on its panel. A PC interface for data transfer is also required, and power has to be supplied from an external ac/dc adapter. The overall construction goal is to illustrate a practical implementation of various electronic and mechanical components, rather than to achieve a high-performance and space-saving design solution. First, the MCAD tool is used to define the PCB shape, dimensions, and mounting holes within the context of the given enclosure. Students are provided with the prebuilt model of the plastic enclosure, constructed as shown in Fig. 3. After sketching the block diagram of the instrument’s circuitry, an

ECAD tool is used to define a PCB with the layout divided into separate rooms, as shown in Fig. 4. Each room on the PCB corresponds to the appropriate block of the circuitry. Then, the electrical design of the main blocks is performed, leaving the expansion blocks empty for the class exercises. At this point, students are introduced to the associations between the schematic symbols, footprints, and 3-D models of the components. In this, emphasis is placed on the board connectors: a 2.1-mm dc power barrel jack for the power supply, a three-pole mini-DIN socket for the external sensor, a reset button for the microcontroller, and a USB-type B receptacle connector for the PC interface. The arrangement and position of the connectors on the PCB with respect to the rear panel of the enclosure are determined by using an MCAD tool, as shown in Fig. 5. The 3-D models are provided by the connector manufacturers. As well as using components from the standard libraries, students are shown how to define their own symbols, footprints, and 3-D models. While most of the components’ 3-D bodies may be represented with simple shapes such as a cylinder and box, a special shape may be required for some. An example is shown in Fig. 6 where a linear voltage regulator in a TO-220 case is mounted on a heatsink. The model of the heatsink is created in the MCAD tool using the


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Fig. 7. 3-D model of the PCB designed in the ECAD tool and prepared for import into the MCAD tool. Fig. 8. 3-D model of the assembled instrument.

manufacturer’s technical drawings. Although every MCAD program contains a rich set of modeling features, only a few features are necessary to create usable models for this purpose. Two MCAD techniques essential for creating 3-D models are covered: extrude (adding material) and cutout (removing material). The level of detail for the 3-D model is also considered. For a purely electromechanical design, only a simple shape is required; in this case, fins can be modeled as two monoblocks of material to represent the overall heatsink dimensions. If a thermal simulation of the PCB is to be performed, however, a detailed model of the fins is required. The next phase introduces conventional PCB design techniques, covering definition of design rules, layout, routing, and so on. The components are placed on the top surface of a two-layer board. Each block from Fig. 4 is designed within its own specific room, and then these rooms are interconnected. Design concepts related to signal integrity are covered [4], and power decoupling, bypass, and grounding techniques are explained. The topic of electromagnetic interference (EMI) is introduced, as are components such as common mode filters and ferrite beads, along with layout techniques to illustrate practices for EMI minimization. Transient voltage suppression (TVS) and electrostatic discharge (ESD) protection techniques are also covered. The USB port is used as a design example for ESD protection methods and differential pair routing. Microstrip lines are explained only at a basic level because they are treated extensively in other courses (specified in Section II). Once the PCB design has been completed, a 3-D model is prepared for import into an MCAD tool as shown in Fig. 7. The instrument should have four devices mounted on the front panel: an on–off switch, a power LED, a 2 16 LCD character display, and a single-turn linear potentiometer for regulating LCDs’ backlight intensity. Appropriate board-to-wire headers are also inserted on the PCB, along with other connectors such as test, programming, and service jumpers.

The assembly procedure of the instrument is completed in the MCAD tool using imported PCB and other device models as shown in Fig. 8. Harnessing is also carried out, so that each of the front panel devices is connected to the corresponding PCB header. Harnessing is an important consideration because it may reveal the need to reposition the PCB headers to improve their accessibility within the housing. It can also show if there is a misalignment between the pins located on PCB headers and panel connectors, which could lead to undesirable crossing and twisting of cables, resulting in EMI issues. Harnessing is used to determine the proper lengths for cables, to facilitate comfortable assembly and disassembly, and to avoid unnecessary jamming. Since harnessing is demanding in terms of the required modeling skills, students are only given a rough overview of the process. Assembly modeling is then carried out to detect part collisions. Exploded views (similar to that in Fig. 3) are used to check the feasibility of mounting all of the parts. Worst-case tolerance requirements are used in order to ensure fit between parts. Possible subassemblies are also identified. For example, two wires are mounted into the receptacle crimp, and opposite ends are soldered to the lugs of the on–off switch. The whole subassembly is inserted through the mounting hole on the front panel. Finally, the switch is fixed with a nut and the crimp housing is mated to the appropriate header on the PCB (Fig. 8). The ease of access to critical parts, either for service or for calibration (test points, trimpots), is also considered. This assembly, harnessing, subassembly, and accessibility exercise is used as an introduction to design for manufacturability. Once the modeling process has been completed, a procedure for creating fabrication outputs is demonstrated. Gerber files, a bill of materials (BOM), and assembly drawings are created using the ECAD and MCAD tools. Particular attention is given to the completeness of the BOM, to include hardware such as

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Fig. 9. Assembled instrument, with the external sensor to measure temperature.

the insulating kit for the TO-220 case and heatsink (Fig. 6). When producing documentation, students are instructed to obey drawing and marking standards and to avoid ambiguities by updating documents (including assembly drawings) with instruction notes [21]. The built instrument is shown in Fig. 9. An external sensor is used to measure temperature. The firmware is provided to the students “as is” and can be changed using the In Circuit Serial Programming (ICSP) header on the PCB. The course finishes by demonstrating advanced techniques in multilayer PCB design and ways to exchange data between ECAD and MCAD tools for thermal and system cooling simulations [22]. IV. ASSESSMENTS Having to imagine and design a product from scratch was a major challenge for students. They had to shift from solving specific problems, such as examples from textbooks and classes, to developing a complete product. Because of this, a formative assessment strategy was developed for the course. The mean value of students’ grades (MV) from their prerequisite courses was (on 1–5 scale) and standard deviation , considered to be adequate for them to absorb the course content. The prerequisite course curricula had focused more on providing theoretical background in the field, with the practical aspects of electronic circuit design having been illustrated by creation of prototypes, consisting of components with predefined types and values, at a breadboard level. Students had not worked with complex circuitry, of some tens of components (or more) organized in functional blocks. Such circuitries are typically arranged on a PCB rather than on a breadboard. Therefore, the entering students’ PCB design experience is expected to be low, as was confirmed by their self-evaluation, shown in Fig. 10. Also, their MCAD experience was generally very low. Consequently, course activities are tailored for students with a good theoretical background, practical experience

Fig. 10. Students’ self-evaluation of their previous PCB design and MCAD experience (grades ranging from 1 to 5: 1—very low; 2—below average; 3—average; 4—above average; 5—very high).

of relatively simple circuits, low PCB design experience, and no MCAD experience. The first of these course activities is designed to improve students’ ability to use technical literature other than textbooks, such as datasheets and application notes. They are shown how to recognize the most significant data from datasheets and how to choose a suitable component from the many alternatives. They are also shown the circuit design and corresponding PCB layout techniques recommended by manufacturers in their application notes—for example, for a crystal oscillator or operational amplifier. The significance of various parameters (including equivalent series resistance, ripple current, and thermal resistance) in the electrical design is highlighted. PCB trace impedances are also considered, with emphasis being given to understanding the effects parameters may have on circuit performance once the schematics have been transferred to a PCB. Laboratory exercises mainly focus on ECAD. The students are divided into two-person teams, with one working on the design, and the other checking the work. The roles rotate within the team so that knowledge acquisition and workload are shared equally. The aim is to emphasize the importance of checking during the design process, in particular on establishing the correspondence between electrical symbols, packages, and footprints. The students are asked to modify part of the presented design by replacing the existing components with others (e.g., to modify the power supply section with SMD tantalum instead of through-hole aluminum electrolytic capacitors, or to use a voltage regulator in the package with a different thermal resistance, so the PCB copper has to be used as a heatsink) and make appropriate layout and routing changes. The teams are encouraged to collaborate in the sense of estimating whether and how their changes would affect the rest of the design. Discussions are moderated to ensure that each team member is involved in every aspect of the design. Homework assignments are MCAD-related, mainly because there is a steep learning curve associated with mid-range MCAD tools, since the basic modeling techniques are simple and almost


TABLE II STUDENTS’ PROGRESS EVALUATION SUMMARY. W7 AND W14 REFER TO WEEKS 7 AND 14 IN TABLE I, RESPECTIVELY

every student has had previous experience with some kind of 3-D graphics. Assembly constraints, like mating faces or axial align between parts, are intuitive and self-explanatory. Typical assignments are to create 3-D models of parts such as switches, heatsinks, or displays and to incorporate PCB model changes from previous exercises into the assembly in accordance with the principle illustrated in Fig. 2. The teams’ solutions are presented to the whole group and discussed with instructors. Teamwork helps students to accumulate knowledge by exchanging acquired know-how on the related subject-matter. Every student should have been able to find useful information, such as design tips [23] or guidelines, and to share it with others. Students’ efficiency in perceiving and selecting significant data from the huge amount available in the literature grew significantly through the course, as shown in Table II. The assessment results lead to the conclusion that students were much more willing to fill their knowledge gaps when faced with practical challenges in both ECAD and MCAD. As a consequence, their solutions are mainly errorless in terms of functionality, and errors in component selection or an ugly PCB layout are also rare mistakes. However, incomplete BOMs were common since students regularly forget to include external parts in their designs. Introducing the practice of error checking within the team was found to be useful because it helped to eliminate many subtle errors in the various design phases. The teams showed a reasonable level of responsibility in completing tasks because they saw the results of their efforts within the scope of the complete product design and clearly understood that the success of the project was strongly dependent on their collaboration. The summative assessment was carried out by assigning the students to redefine or design complete rooms on the board from Fig. 4, in tasks such as the following: — changing the linear voltage regulator circuitry with a switching regulator; — changing the sensor signal conditioning circuitry to accommodate a resistive temperature device instead of a silicon temperature sensor; — changing the USB interface with RS232; — adding a data logging circuitry using a SD card within the expansion room; — adding a machine-to-machine talk capability using cellular data module within the expansion room. These tasks are related not only to the electrical part of the design, but also to the mechanical design, so as to incorporate various electromechanical parts (board connectors, SD and SIM card holders, antenna, etc.) within the enclosure. Each task was

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TABLE III ASSESSMENT RESULTS FOR ANSWERS TO TASK QUESTIONS (PERCENTAGE ROUNDED)

Fig. 11. Exam results (grades ranging from 1 to 5: 1—passing; 2—satisfactory; 3—good; 4—very good; 5—excellent).

assigned to a student pair to promote collaborative work. After presenting their solutions, each student was asked to provide additional explanations. Questions were related not only to the set tasks, but also to the other topics on the syllabus; sample question topics include current loops in the switching power supply circuitry or the antenna impedance matching of a cellular module. Apart from checking overall knowledge acquired through the course, this also minimized the possibility of weaker students being carried by their teammate. The assessment results for these questions are shown in Table III. Final grades (the exam results) are assigned on the basis of the quality of the solutions and answers to the questions, with a distribution as shown in Fig. 11. The post-course student anonymous survey was conducted on a group of 27 students. They were given the opportunity to add comments and notes to their rankings. The survey results related to major learning outcomes are shown in Fig. 12, showing that 85% of students fully understood the design process workflow presented. This percentage nearly corresponds to the sum of grades in the range 3–5 from Fig. 11. Also, 75% of students indicated that extensive use of 3-D visualization and interaction between ECAD and MCAD tools contributed significantly to their understanding of the subject matter. Students’ level of

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Fig. 12. Survey grades for the questions related to learning outcomes (grades range from 1 to 5: 1—strongly disagree; 2—disagree; 3—neither agree nor disagree; 4—agree; 5—strongly agree).


Fig. 14. Survey grades for questions related to the students overall course impression (grades range from 1 to 5: 1—strongly disagree; 2—disagree; 3—neither agree nor disagree; 4—agree; 5—strongly agree).

As shown in Fig. 14, the course is evaluated by the students as being very rewarding. Student comments highlight as an advantage the ability to use full-featured and production-oriented CAD tools. Other comments regret the lack of laboratory classes for the exercises, which is attributable to students’ expectations for a better connection between theory and practice, and is consistent with observations reported in other studies [24], [25]. V. CONCLUSION

Fig. 13. Survey grades for questions on students’ teamwork experience (grades range from 1 to 5: 1—strongly disagree; 2—disagree; 3—neither agree nor disagree; 4—agree; 5—strongly agree).

confidence after the course to undertake a PCB design is significant when compared to their pre-course experience, shown in Fig. 10. The survey results indicated that the MCAD part of the design was easier to understand than the ECAD (63% versus 37%), which matches the results from Table II. Also, 90% of students strongly agree that the examples are appropriate for the course with none disagreeing; this validates the orientation of the course toward real-world engineering by considering the PCB as a part of the final product. An important conclusion can be drawn from the survey results shown in Fig. 13. It is obvious that the students considered teamwork crucial for successful mastering of the subject-matter content. A surprisingly high percentage of students associated teamwork with an improvement in their creativity, which they attributed to the know-how picked up from their team members and from discussions with other teams.

A PCB design course has been developed so that the design of PCBs is incorporated in the scope of the complete electronic product. The teaching methodology, based on the course project, exploited advanced interaction between ECAD and MCAD tools and assumed that electromechanical devices required as much attention as electrical ones. The introduction of MCAD clearly had a positive impact in achieving the expected learning outcomes. A potential drawback may be that some PCB-specific topics related to circuit theory received less attention than they otherwise would, so as to give students more practical experience. Achieving a balance between the amount of the material covered and the time required to transform this to working knowledge is the main goal of the course refinement process. REFERENCES [1] K. Feldmann and J. Franke, “Computer-aided planning systems for integrated electronic and mechanical design,” IEEE Trans. Compon., Hybrids, Manuf. Technol., vol. 16, no. 4, pp. 377–383, Jun. 1993. [2] M. Montrose, EMC and the Printed Circuit Board: Design, Theory, & Layout Made Simple. New York, NY, USA: IEEE Press, 1999. [3] C. Coombs, Printed Circuits Handbook, 6th ed. New York, NY, USA: McGraw-Hill, 2008. [4] Signal Integrity Issues and Printed Circuit Board Design, D. Brooks, Ed. Upper Saddle River, NJ, USA: Prentice Hall, 2003. [5] M. Krishnan, S. Das, and S. A. Yost, “A 10-year mechatronics curriculum development initiative: Relevance, content, and results—Part II,” IEEE Trans. Educ., vol. 53, no. 2, pp. 202–208, May 2010. [6] K. Mitzner, Complete PCB Design Using OrCAD Capture and PCB Editor. Oxford, U.K.: Newnes, 2009.


[7] Altium Limited, Shanghai, China, “Altium Designer 10,” 2011 [Online]. Available: http://www.altium.com [8] National Instruments, Austin, TX, USA, “NI Ultiboard—Printed circuit board layout and routing,” 2011 [Online]. Available: http://www.ni.com/ultiboard [9] Mentor Graphics, Wilsonville, OR, USA, “PADS PCB design tools,” 2011 [Online]. Available: http://www.mentor.com [10] Siemens PLM Software, Plano, TX, USA, “Solid Edge ST4,” 2011 [Online]. Available: http://www.plm.automation.siemens.com [11] Dassault Systèmes SolidWorks Corp., Waltham, MA, USA, “Solid Works 2012,” 2012 [Online]. Available: http://www.solidworks.com [12] Autodesk Inc., San Rafael, CA, USA, “Autodesk Inventor,” 2011 [Online]. Available: http://www.autodesk.com [13] L. Man, D. Pitica, and M. Zolog, “Electrical/mechanical/thermal design integration,” in Proc. 15th SIITME, Gyula, Hungary, Sep. 2009, pp. 161–165. [14] M. Bourbel, “Electronic information exchange,” Electron. Cooling, vol. 8, pp. 24–32, Nov. 2002. [15] J. Kim, M. J. Pratt, R. G. Iyer, and R. D. Sriram, “Standardized data exchange of CAD models with design intent,” Comput. Aided Design, vol. 40, pp. 760–777, Jul. 2008. [16] Parametric Technology Corporation (PTC), Needham, MA, USA, “Windchill Gateway for Cadence Allegro Design Workbench (ADW),” Data Sheet, 2010 [Online]. Available: http://www.ptc.com [17] D. Kehmeier, “Integrating PCB layout and mechanical design,” Printed Circuit Design Fab Mag., vol. 29, pp. 33–37, Jul. 2012. [18] K. Chen, “MCAD-ECAD integration constraint modeling and propagation” Ph.D. dissertation, Georgia Institute of Technology, Atlanta, GA, USA, 2008 [Online]. Available: http://hdl.handle.net/1853/26484 [19] K. Chen, J. Bankston, J. H. Panchal, and D. Schaefer, “A framework for integrated design of mechatronic systems,” in Collaborative Design and Planning for Digital Manufacturing. London, U.K.: Springer, 2009, pp. 37–70. [20] K. M. Waldenmeyer and N. W. Hartman, “Multiple CAD formats in a single product data management system: A case study,” J. Ind. Technol., vol. 25-3, pp. 2–7, Jul. 2009. [21] C. Robertson, Printed Circuit Board Designer’s Reference: Basics. Upper Saddle River, NJ, USA: Prentice-Hall, 2003. [22] J. Isaac, “Electronic system design,” Printed Circuit Design Fab Mag., vol. 25, pp. 24–27, Dec. 2008. [23] B. Archambeault, “Resistive vs. inductive return current paths,” IEEE EMC Soc. Newslett., no. 219, pp. 81–83, Fall 2008. [24] E. Taslidere, F. Cohen, and F. Reisman, “Wireless sensor networks—A hands-on modular experiments platform for enhanced pedagogical learning,” IEEE Trans. Educ., vol. 54, no. 1, pp. 24–33, Feb. 2011. [25] M. Radu, C. Cole, M. Dabacan, J. Harris, and S. Sexton, “The impact of providing unlimited access to programmable boards in digital design education,” IEEE Trans. Educ., vol. 54, no. 2, pp. 174–183, May 2011. Danijel Danković (M’98) received the B.S., M.S., and Ph.D. degrees in electrical engineering from the University of Niš, Niš, Serbia, in 2001, 2006, and 2009, respectively. He has been a member of the Academic Staff with the Department of Microelectronics, Faculty of Electronic Engineering, University of Niš, since 2001, where he is currently a Teaching Assistant in the courses PCB Design, Electronic Devices, Devices for Telecommunications, Analog Microelectronics, and Digital Microelectronics. He has authored or coauthored over 40 papers published in the international journals and conference proceedings. His research is focused on negative bias temperature instability (NBTI) in MOS devices.

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Ljubomir Vračar (M’99) received the B.S. and M.S. degrees in electrical engineering from the University of Niš, Niš, Serbia, in 1999 and 2009, respectively. He has been a member of the Academic Staff with the Department of Microelectronics, Faculty of Electronic Engineering, University of Niš, since 2002. His activities as a Teaching Assistant include the courses Electronic Devices, PCB Design, and Sensors. He gained much pedagogical experience by performing a large number of lab experiments during his studies and was engaged in development and modernization of teaching material. Between 2001 and 2007, he was the Head of the Applied Physics and Electronics Department, Petnica Science Centre, Valjevo, Serbia, when he worked on establishing international cooperation with the Weizman Institute of Science in Israel in the field of communications and education of young talents. He has authored or coauthored over 30 papers published in the national and international journals and conference proceedings. He is currently working on embedded controller systems and smart sensor design, especially in the field of home automation and energy harvesting.

Aneta Prijić (M’91) received the B.S., M.S., and Ph.D. degrees in electrical engineering from the University of Niš, Niš, Serbia, in 1993, 1996, and 2007, respectively. She has been a member of the Academic Staff with the Department of Microelectronics, Faculty of Electronic Engineering, University of Niš, since 1995. She is currently an Assistant Professor in the courses Semiconductor Devices, Design of Microsystems, and Integrated Microsystems. She has authored or coauthored over 40 papers in the international journals and conference proceedings. Her main research areas are modeling and simulation of electrical and electronic devices, microelectromechanical, and energy-harvesting systems.

Zoran Prijić (M’91) received the B.S., M.S., and Ph.D. degrees in electrical engineering from the University of Niš, Niš, Serbia, in 1987, 1990, and 1993, respectively. He joined Ei-Microelectronics, Niš, Serbia, in 1987, working initially on CMOS integrated circuits and then on power MOS transistors technology development. In 1990, he joined the Academic Staff, Faculty of Electronic Engineering, University of Niš, where he is currently Head of the Department of Microelectronics. He is a Full Professor in the courses Electronic Devices, PCB Design, Analog Microelectronics, and Digital Microelectronics. He was Head of the Laboratory for Microelectronics and Head of the Computer Center. From 2001 to 2006, he was a Research and Development Vice-President of Ei Holding Co, Niš, Serbia. He has authored or coauthored over 50 papers in the international technical literature. His area of research is modeling and simulation of electronic components and microelectromechanical systems, while his technical interest includes industrial informatics.