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GLOSSARY of Printed Circuits

by John Walt Childers, IPC-CID, Founder of Golden Gate Graphics

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Pronunciation Key

Golden Gate Graphics in an official Altium Service Bureau

Golden Gate Graphics is an official Altium Service Bureau

Terms that contain digits are alphabetized as if the numeric characters were spelled in English.

Terms with two or more words are alphabetized "dictionary style." They are alphabetized as though the spaces between the terms have been removed.
   If there are other characters in the term, such as a slash (/), these are treated the same as spaces and ignored for the purpose of alphabetizinig.

TOP       L

Index to terms on this page:

laser photoplotter   lead   leadframe   LGA  
liquid photoimageable solder mask   LPI  

laser photoplotter — (also "laser plotter") A photoplotter which simulates a vector photoplotter by using software to create a raster image of the individual objects in a CAD file, then plotting the image as a series of lines of dots at very fine resolution. A laser photoplotter is capable of more accurate and consistent plots than a vector photoplotter.
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lead — (LEED) Pronunciation Key noun [PCB Components] A terminal on a component.
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lead frame — (LEED-fraym)  Pronunciation Key  noun  [Component Manufacturing] The metal frame that semiconductors are attached to during the package assembly process. Typically a lead frame is a long metal frame with positions for multiple chips.
After the chips are attached to the lead frame tiny wires are used to connect the chip bond pads to the frame and then the positions on the frame where chips are located are encapsulated in epoxy. (shown in Fig. 6.77). Leadframe With Encapsulated Packages
   At this point, the leadframe package goes through a solder plating process whereby the metal fram with the leads are plated with a tin-lead or lead-free tin or tin alloy finish. After the plating step, the metal frame goes through a trim-and-form process whereby leads are separated from the frame and each package is diced, separated and made ready for assembly (Fig. 6.78).Singulation From Leadframe Leadframes_Modern_Electroplating_5th Ed_Mordechay_Schlesinger
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LGA — (EL GEE AY) Pronunciation Key

  1. noun [Components] Land Grid Array
    The following is a good illustrated explanation of Land Grid Arrays. This is from Intel, who has used LGAs for many of their CPUs (Central Processing Units). 
  3. Leadless Chip Carrier is sometimes used as a meaning for LGA. This is a misnomer. It is incorrect. Leadless chip carriers are usually not grids, but instead are quad packages. Quad packages have four rows of lands forming a rectangular shape.

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liquid photoimageable solder mask (LPI) — A mask sprayed on using photographic imaging techniques to control deposition. It is the most accurate method of mask application and results in a thinner mask than dry film solder mask. It is often preferred for dense SMT.
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LPI — stands for Liquid PhotoImageable. Refers to liquid photoimageable solder mask.
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Example Printed Boards

Click for Examples of PCBs designed by Golden Gate Graphics

References and Dictionaries

Modern Dictionary of Electronics by Rudolf F. Graf

This is the best, most usable dictionary for electronics, because its definitions help you grasp the terms and therefore the subject. Lesser dictionaries define electronics terms with even more difficult technical jargon, leading one into endless "word chains." Not this one.
You can buy the Modern Dictionary of Electronics new or used via the Internet.

Graf, Rudolf F. Modern Dictionary of Electronics. Newnes, 1999.

The Random House Dictionary of the English Language, Unabridged, 2nd Edition

You need a big, comprehensive dictionary. Get this one. Despite being a big dictionary, The Random House has great definitions, quick to grasp.

Although out of print, as of 2020 you could still buy a great used copy online for $30 including shipping or possibly for much less. Two versions are available of the 2nd Edition, Unabridged:

I have no idea what the difference is for the deluxe edition, but there seem to be fewer copies of it available in 2020 than the regular edition. I'm sure they both have the same set of definitions. My copy has both ISBNs listed in the front matter, and it is the regular edition.

Flexner, Stuart Berg, and Leonore Crary Hauck, editors. The Random House Dictionary of the English Language. Unabridged, 2nd Edition, Random House, 1987.