A teardrop is typically drop-shaped feature on a

printed circuit board A printed circuit board (PCB), also called printed wiring board (PWB), is a Lamination, laminated sandwich structure of electrical conduction, conductive and Insulator (electricity), insulating layers, each with a pattern of traces, planes ...

and can be found on the junction of

via Via or VIA may refer to the following: Arts and entertainment * ''Via'' (Volumes album), 2011 * Via (Thalia Zedek album), 2013 * VIA (music), Soviet and Russian term for a music collective Businesses and organisations * Via Foundation, a Cz ...

s or

contact pad Contact pads or bond pads are small, conductive surface areas of a printed circuit board (PCB) or die of an integrated circuit. They are often made of gold, copper, or aluminum and measure mere micrometres wide. Pads are positioned on the edges o ...

Purpose

The main purpose of teardrops is to enhance

structural integrity ''Structural Integrity'' is a scientific book series covering the research field and technical view of the structural integrity and failure area. The series was established in 2017 and is published by Springer Science+Business Media. The editors-i ...

in presence of thermal or

mechanical stress In continuum mechanics, stress is a physical quantity that describes forces present during deformation. For example, an object being pulled apart, such as a stretched elastic band, is subject to ''tensile'' stress and may undergo elongatio ...

es, for example due to vibration or flexing. Structural integrity may be compromised, e.g., by misalignment during drilling, so that too much

copper Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...

may be removed by the drill hole in the area where a trace connects to the pad or via. An extra advantage is the enlarging of manufacturing tolerances, making manufacturing easier and cheaper.

Shape

While a typical shape of a teardrop is straight-line tapering, they may be concave. This type of teardrop is also called ''filleting'' or ''straight''. To produce a ''

snowman A snowman is an Anthropomorphism, anthropomorphic snow sculpture of a man often built in regions with sufficient snowfall and is a common winter tradition. In many places, typical snowmen consist of three large snowballs of different sizes wit ...

''-shaped teardrop, a secondary pad of smaller size is added at the junction overlapping with the primary pad (hence the nickname).

Necking

For similar reasons, a technique called ''trace necking'' reduces (or ''necks down'') the width of a trace that approaches a narrower pad of a

surface-mounted device Surface-mount technology (SMT), originally called planar mounting, is a method in which the electrical components are mounted directly onto the surface of a printed circuit board (PCB). An electrical component mounted in this manner is referred ...

or a

through-hole In electronics, through-hole technology (also spelled "thru-hole") is a manufacturing scheme in which leads on the components are inserted through holes drilled in printed circuit boards (PCB) and soldered to pads on the opposite side, either ...

with a diameter that is less than the width of the trace, or when the trace passes through bottlenecks (for example, between the pads of a component).

References

External links

{{commonscat
High Frequency PCB
Printed circuit board manufacturing