Teardrop (electronics)

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

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

Contents

Purpose

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

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

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]

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<span class="mw-page-title-main">Surface-mount technology</span> Method for producing electronic circuits

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<span class="mw-page-title-main">Gerber format</span> Standard file format used for designing printed circuit boards

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<span class="mw-page-title-main">Through-hole technology</span> Circuit board manufacturing technique

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This page is a comparison of electronic design automation (EDA) software which is used today to design the near totality of electronic devices. Modern electronic devices are too complex to be designed without the help of a computer. Electronic devices may consist of integrated circuits (ICs), printed circuit boards (PCBs), field-programmable gate arrays (FPGAs) or a combination of them. Integrated circuits may consist of a combination of digital and analog circuits. These circuits can contain a combination of transistors, resistors, capacitors or specialized components such as analog neural networks, antennas or fuses.

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<span class="mw-page-title-main">PCB (software)</span>

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<span class="mw-page-title-main">DesignSpark PCB</span>

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<span class="mw-page-title-main">DipTrace</span>

DipTrace is a proprietary software suite for electronic design automation (EDA) used for electronic schematic capture and printed circuit board layouts. DipTrace has four applications: schematic capture editor, PCB layout editor with built-in shape-based autorouter and 3D preview, component editor, and pattern editor.

<span class="mw-page-title-main">Autotrax</span>

Autotrax was a free software application that ran on DOS on an IBM or compatible PC. It was designed by Protel Systems, and was one of the first professional printed circuit board CAD applications available for personal computers. It is a freeware download and also available in a stripped-down version marketed as Easytrax.

CircuitMaker is electronic design automation software for printed circuit board designs targeted at the hobby, hacker, and maker community. CircuitMaker is available as freeware, and the hardware designed with it may be used for commercial and non-commercial purposes without limitations. It is currently available publicly as version 2.0 by Altium Limited, with the first non-beta release on January 17, 2016.

EasyEDA is a web-based EDA tool suite that enables hardware engineers to design, simulate, share - publicly and privately - and discuss schematics, simulations and printed circuit boards. Other features include the creation of a bill of materials, Gerber files and pick and place files and documentary outputs in PDF, PNG and SVG formats.

Specctra is a commercial PCB auto-router originally developed by John F. Cooper and David Chyan of Cooper & Chyan Technology, Inc. (CCT) in 1989. The company and product were taken over by Cadence Design Systems in May 1997. Since its integration into Cadence's Allegro PCB Editor, the name of the router is Allegro PCB Router. The latest version is 17.4 – 22.1.

References

  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. 1 2 3 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. 1 2 3 4 5 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. 1 2 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. 1 2 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.
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