In printed circuit boards, teardrops are typically drop-shaped features at the junction of vias (''teardrop vias'') or

contact pad Contact pads or bond pads are designated surface areas of a printed circuit board (PCB) or die of an integrated circuit. Possibilities to contact to pads include soldering, wirebonding, flip chip Flip chip, also known as controlled collapse ...

s (''teardrop pads'') and traces (''teardrop traces''). The main purpose of teardrops is to enhance

structural integrity Structural integrity and failure is an aspect of engineering that deals with the ability of a structure to support a designed structural load (weight, force, etc.) without breaking and includes the study of past structural failures in order to ...

in presence of thermal or

mechanical stress In continuum mechanics, stress is a physical quantity. It is a quantity that describes the magnitude of forces that cause deformation. Stress is defined as ''force per unit area''. When an object is pulled apart by a force it will cause elonga ...

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

''-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 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 by ...

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

{{reflist, refs= {{cite web , title=Component placement tips and strategies , author-first=Mahmoud , author-last=Wahby , date=2014-02-21 , publisher= EDN Network , url=http://www.edn.com/design/pc-board/4428665/2/Component-placement-tips-and-strategies , access-date=2017-09-24 , url-status=live , archive-url=https://web.archive.org/web/20170924154358/http://www.edn.com/design/pc-board/4428665/2/Component-placement-tips-and-strategies , archive-date=2017-09-24 {{cite web , title=Removing Unused Pads and Adding Teardrops , work=

Altium Designer Altium Designer (AD) is a PCB and electronic design automation software package for printed circuit boards. It is developed by Australian software company Altium Limited. History Altium Designer was originally launched in 2005 by Altium, ...

technical documentation , publisher=

Altium Altium Limited is an Australian multinational software company that provides electronic design automation software to engineers who design printed circuit boards. Founded as Protel Systems Pty Ltd in Australia in 1985, the company has regional ...

, date=2017-05-30 , author-first=Phil , author-last=Loughhead , url=http://www.altium.com/documentation/17.1/display/ADES/((Removing+Unused+Pads+and+Adding+Teardrops))_AD , access-date=2017-09-24 , url-status=live , archive-url=https://web.archive.org/web/20170924154600/http://www.altium.com/documentation/17.1/display/ADES/((Removing+Unused+Pads+and+Adding+Teardrops))_AD , archive-date=2017-09-24 {{cite web , title=Why Where When and how teardrops should be added to PCB? , author-first=Amos , author-last=Kolath , date=2010 , publisher=KaiZen Technologies , url=http://www.kaizen-t.com/technical/teardropinpcb.html , access-date=2017-09-24 , url-status=live , archive-url=https://web.archive.org/web/20170924160524/http://www.kaizen-t.com/technical/teardropinpcb.html , archive-date=2017-09-24 {{cite web , title=PCB Design Guidelines for 0.5mm Package-on-Package Applications Processor, Part I , author-first1=Keith G. , author-last1=Gutierrez , author-first2=Keven , author-last2=Coates , publisher=

Texas Instruments Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globa ...

, id=Application Report SPRABB3 , date=June 2010 , url=http://www.ti.com/lit/an/sprabb3/sprabb3.pdf , access-date=2015-07-27 , url-status=live , archive-url=https://web.archive.org/web/20170924161459/http://www.ti.com/lit/an/sprabb3/sprabb3.pdf , archive-date=2017-09-24 {{cite web , title=Empfehlung zu Tear-drops , trans-title=Recommendations for tear-drops , author-first=Wilhelm , author-last=Lobner , language=German , publisher=AT&S AG, Fachverband Elektronik-Design e.V. (FEV) , date=October 2002 , url=http://wiki.fed.de/images/5/50/Empfehlung_zu_Tear-drops.pdf , access-date=2017-09-24 , url-status=live , archive-url=https://web.archive.org/web/20170924171544/http://wiki.fed.de/images/5/50/Empfehlung_zu_Tear-drops.pdf , archive-date=2017-09-24 {{cite web , title=Interactive Routing , work=

technical documentation , publisher=

, date=2017-04-25 , author-first=Phil , author-last=Loughhead , url=http://www.altium.com/documentation/17.1/display/ADES/((Interactive+Routing))_AD , access-date=2017-09-24 , url-status=live , archive-url=https://web.archive.org/web/20170924200151/http://www.altium.com/documentation/17.1/display/ADES/((Interactive+Routing))_AD , archive-date=2017-09-24 {{cite patent , title=Packaging Electronic Systems , country=US, number=3560256 , pubdate=1971-02-02 , fdate=1966-10-06 , pridate=1966-10-06 , inventor-first=Halle , inventor-last=Abrams , assign= Western Electric Co. {{cite book , title=Printed Circuit Board Design with Microcomputers , author-first=T. J. , author-last=Byers , edition=1 , publisher= Intertext Publications/Multiscience Press, Inc.,

McGraw-Hill Book Company McGraw Hill is an American educational publishing company and one of the "big three" educational publishers that publishes educational content, software, and services for pre-K through postgraduate education. The company also publishes referen ...

, location=New York, USA , date=1991-08-01 , isbn=0-07-009558-2 , lccn=91-72187 , page=102 , url=https://dl.acm.org/citation.cfm?id=114661 {{cite book , title=The Electronics Handbook , editor-first1=Jerry C. , editor-last1=Whitaker , editor-first2=Richard C. , editor-last2=Dorf , author-first1=Ravindranath , author-last1=Kollipara , author-first2=Vijai K. , author-last2=Tripathi , author-first3=Jerry E. , author-last3=Sergent , author-first4=Glenn R. , author-last4=Blackwell , author-first5=Donald , author-last5=White , author-first6=Zbigniew J. , author-last6=Staszak , chapter=11.1.3 Packaging Electronic Systems - Design of Printed Wiring Boards , publisher= CRC Press, Taylor & Francis Group, LLC , date=2005 , edition=2 , isbn=978-0-8493-1889-4 , lccn=2004057106 , page=1266 , chapter-url=http://s1.downloadmienphi.net/file/downloadfile6/192/1385077.pdf , access-date=2017-09-25 , url-status=live , archive-url=https://web.archive.org/web/20170925235855/http://s1.downloadmienphi.net/file/downloadfile6/192/1385077.pdf , archive-date=2017-09-25 {{cite book , title=High-Speed Circuit Board Signal Integrity , author-first=Stephen C. , author-last=Thierauf , publisher= Artech House, Inc. , location=Norwood, MA, USA , date=2004 , edition=1 , isbn=1-58053-131-8 , pages=104–105 , url=http://plrtzglrb.hu/ghz/books/Artech House.High.speed.Circuit.Board.Signal.Integrity.eBook.pdf , access-date=2017-09-26 , url-status=live , archive-url=https://web.archive.org/web/20170926004619/http://plrtzglrb.hu/ghz/books/Artech%5b1%5d.House.High.speed.Circuit.Board.Signal.Integrity.eBook.pdf , archive-date=2017-09-26

External links

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