Master Thesis - OUFTI-1

Now, the question is: When each method can be applied and why
To answer to this question, it should be noted that electronic components can be divided
into three categories:
• Light components: This category includes small discrete components, such as
resistors or transistors. The mass and stiness of these particular components are so
small than they can be neglected. So, in general, the simple method is applied to
these components.
• Surface Mount Technology (SMT) components: This category symbolizes
components such as Quad Flat Pack (QFP) Ball Grid Array (BGA) and Pin Grid
Array (PGA), which are generally about 10 − 30 mm square. The mass and stiness
increases of these particular components are proportional to their length and inversely
proportional to the thickness of the PCB on which they are soldered. So, in general,
the global or local smearing methods are applied to these components.
• Heavy components: This category includes large components, such as transformers,
large power capacitors and resistors. Due to their important mass and stiness,
these components are generally modeled using a local smearing method or, more
rarely, a detailed FE model.
These categories are illustrated in Figure 4.9.
Figure 4.9: Illustration of the dierent categories of components [45]
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