📑 Table of Contents▼

Teardrops and trace necking as seen in a PCB layout design tool
Teardrop vias on printed circuit boards

A teardrop is typically drop-shaped feature on a printed circuit board (PCB) and can be found on the junction of vias or contact pads.

Purpose

edit

The main purpose of teardrops is to enhance structural integrity in presence of thermal or mechanical stresses,[1][2][3] for example due to vibration or flexing.[4] 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.[2][3][5] An extra advantage is the enlarging of manufacturing tolerances, making manufacturing easier and cheaper.[3]

Shape

edit

While a typical shape of a teardrop is straight-line tapering, they may be concave.[2] This type of teardrop is also called filleting or straight.[3] To produce a snowman-shaped teardrop, a secondary pad of smaller size is added at the junction overlapping with the primary pad (hence the nickname).[3][6]

Necking

edit
See also: Necking (engineering)

For similar reasons, a technique called trace necking reduces (or necks down[7][8][9]) the width of a trace that approaches a narrower pad of a surface-mounted device or a through-hole 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).[8][9][10][11]

References

edit
  1. ^ Wahby, Mahmoud (2014-02-21). "Component placement tips and strategies". EDN Network. Archived from the original on 2017-09-24. Retrieved 2017-09-24.
  2. ^ a b c Loughhead, Phil (2017-05-30). "Removing Unused Pads and Adding Teardrops". Altium Designer technical documentation. Altium. Archived from the original on 2017-09-24. Retrieved 2017-09-24.
  3. ^ a b c d e Kolath, Amos (2010). "Why Where When and how teardrops should be added to PCB?". KaiZen Technologies. Archived from the original on 2017-09-24. Retrieved 2017-09-24.
  4. ^ Ruth (2023-04-28). "Introduction to high speed PCB and is it same as high frequency PCB". IBE Electronics. Retrieved 2023-05-01.
  5. ^ Lobner, Wilhelm (October 2002). "Empfehlung zu Tear-drops" [Recommendations for tear-drops] (PDF) (in German). AT&S AG. Archived (PDF) from the original on 2017-09-24. Retrieved 2017-09-24.
  6. ^ Gutierrez, Keith G.; Coates, Keven (June 2010). "PCB Design Guidelines for 0.5mm Package-on-Package Applications Processor, Part I" (PDF). Texas Instruments. Application Report SPRABB3. Archived (PDF) from the original on 2017-09-24. Retrieved 2015-07-27.
  7. ^ Loughhead, Phil (2017-04-25). "Interactive Routing". Altium Designer technical documentation. Altium. Archived from the original on 2017-09-24. Retrieved 2017-09-24.
  8. ^ a b Byers, T. J. (1991-08-01). Printed Circuit Board Design with Microcomputers (1 ed.). McGraw-Hill Book Company. p. 102. ISBN 0070095582. LCCN 91-72187.
  9. ^ a b Kollipara, Ravindranath; Tripathi, Vijai K.; Sergent, Jerry E.; Blackwell, Glenn R.; White, Donald; Staszak, Zbigniew J. (2005). "11.1.3 Packaging Electronic Systems - Design of Printed Wiring Boards" (PDF). In Whitaker, Jerry C.; Dorf, Richard C. (eds.). The Electronics Handbook (2 ed.). CRC Press. p. 1266. ISBN 978-0-8493-1889-4. LCCN 2004057106. Archived (PDF) from the original on 2017-09-25. Retrieved 2017-09-25.
  10. ^ US 3560256, Abrams, Halle, "Packaging Electronic Systems", published 1971-02-02, assigned to Western Electric Co. 
  11. ^ Thierauf, Stephen C. (2004). High-Speed Circuit Board Signal Integrity (1 ed.). Artech House, Inc. pp. 104–105. ISBN 1580531318.
edit
Wikimedia Commons logo
Wikimedia Commons has media related to Teardrop (electronics).

📚 Artikel Terkait di Wikipedia

Necking (engineering)

cross-sectional area provides the basis for the name "neck". Because the local strains in the neck are large, necking is often closely associated with yielding,

Necking

tension forming a thin neck Necking (electronics), thinning of traces in PCB layouts Necking, a behavior of giraffes Necking up or necking down, methods of

Ductility

(representing the onset of necking) is often relatively flat. Moreover, some (brittle) materials fracture before the onset of necking, such that there is no

TopoR

clearances for each net can be specified. TopoR automatically supports trace necking, that is, it reduces the width of a wire that approaches a narrow pad

Trace (deconstruction)

Trace (French: [tʁas] ) is one of the most important concepts in Derridian deconstruction. In the 1960s, Jacques Derrida used this concept in two of his

List of The Weekly with Charlie Pickering episodes

state’s premier Daniel Andrews claimed several infection clusters have been traced to separate families across multiple households; A Perth man, Cooper Allin

List of The Adventures of Ozzie and Harriet episodes

she's standing next to a car. Thorny tells Ozzie he knows someone who can trace the license plate. The family wants to do things to cheer Ricky up. When

Neck

Inferior to the Adam's apple is the cricoid cartilage. The trachea is traceable at the midline, extending between the cricoid cartilage and suprasternal