GLOSSARY of Printed Circuits

Index to terms on this page:

GAL   gang clearance   gang solder mask   gate   GC-Prevue   gerber   Gerber  
Gerber file  
glob top   GSM   GOST   graphene   GTL   GTLP   GUI   gull wing  

GAL — The Generic Array Logic (also known as GAL) device was an innovation of the PAL and was invented by Lattice Semiconductor. The GAL was an improvement on the PAL because one device was able to take the place of many PAL devices or could even have functionality not covered by the original range. Its primary benefit, however, was that it was eraseable and re-programmable making prototyping and design changes easier for engineers.
Wikipedia - Generic array logic

↑  Page Index

gang clearance — (GANG CLEER-ans)   Pronunciation Key  noun   HDI (High Density Interconnect) A clearance (space or separation) around a group of PCB objects. As this applies especially to solder mask, it is drawn as an object on the solder mask layer to surround fine pitch (0.5-mm-or-less pitch) pads. On the printed board it becomes an opening in the solder mask that exposes copper and provides no solder mask between adjacent pads. See illustration below, example on the left "gang solder mask window."

Source: Epec Engineered Technologies SOLDER MASK DESIGN BASICS.

To create a gang clearance around a group of pads, draw a fill (rectangular object) or region (irregular-shaped object) on the solder mask layer. Because solder mask objects in PCB designs are negative-image (the object represents an absence of material), the shape on the solder mask layer creates an area on the printed board where there is no solder mask.

But use of gang clearances with HDI leads to shorts that have to be re-worked, because there is no solder mask dam (ridge of solder mask between pads) to prevent solder from bridging over from one pad to another. Fine-pitch pads, being so close together, result in solder mask dams that are too narrow (less than 4 mils) to manufacture and so can cause defects (lumps of solder mask) that can interfere with soldering during the assembly of components. Solder mask gang clearances have often been used to prevent this type of defect.

Is there a solution to enable solder mask dams of 4-mils between fine pitch parts? Well, yes. See this article: Design For Assembly-HDI Prevention of Solder Bridging

↑  Page Index

gang solder mask — See gang clearance.

↑  Page Index

gate — (GAYT)   Pronunciation Key  noun  

1. [Electronics] A circuit or digital logic element usually with one output and one or more inputs. If two or more inputs, the output is a function of a combination of the inputs. If one input, the output is always the same. The two-input logic gates perform a computation of Boolean logic.
   
2. [CAE] A symbol in a CAE schematic which represents a functional part of a device, but not the whole device. This system was adapted in CAE shematics based on electronic gates (definition 1) packaged four or six to a device, and then applied to any device with more than one symbol representing its parts. Thus, even a symbol for one pin of a connector came to be called a "gate." (See part definition 4. )

↑  Page Index

GC-Prevue — A CAM file viewer and printer made by Graphicode. Their low cost version can store Gerber and NC Drill files within a file (.GWK extension), which makes it extremely useful for sharing electronic data:   It can be used for importing Gerber files in a logical sequence, displaying them in perfect register , annotating (adding labels to the filenames to describe their use and position in the stackup) and viewing them, saving all that and then passing the resulting .GWK file on to another for examination. Besides merely looking at the files or printing them, GC-Prevue has features for measuring objects' size and relative distance from each other. GC-Prevue sets-up and saves Gerber data in a single file. Free Gerber viewers require one to set up the Gerber files each time and won't allow saving the set-ups unless one buys an upgrade. (From the viewpoint of a printed circuit designer serving engineers or customers, this inability to save set-ups makes the free Gerber viewers completely useless for sharing Gerber data.)

↑  Page Index

gerber or Gerber — see Gerber file.

Gerber file — ASCII data file used to control a photoplotter. Named after H. Joseph Gerber, founder of Gerber Scientific Co., who invented the original vector photoplotter.

↑  Page Index

glob top — A blob of non-conductive plastic, often black in color, which protects the chip and wire bonds on a packaged IC and also on a chip on board. This specialized plastic has a low coefficient of thermal expansion so that ambient temperature changes will not rip loose the wire bonds it is designed to protect. In high-volume chip on board production, these are deposited by automated machinery and are round. In prototype work, they are deposited by hand and can be custom-shaped; however, in designing for manufacturability, one assumes a prototype product will "take- off" and ultimately have high market demand, and so lays out chip on board to accommodate a round glob top with adequate tolerance for machine-driven "slop-over".

↑  Page Index

GSM — Global System for Mobile [tele]communications. English-language expansion eventually adopted for commercialization. Acronym originally stood for Groupe Spéciale Mobile, created in 1982 by the CEPT to develop a pan-European public land mobile system. [In 1989 it became a special subgroup in the ETSI).] Two major implementations are DCS-1800 and PCS-1900.

↑  Page Index

GOST — GOvernmental STandard. GOST refers to a set of technical standards maintained by the Euro-Asian Council for Standardization, Metrology and Certification (EASC). These standards are adhered to by designers throughout the Commonwealth of Independent States (CIS). Support for GOST is implemented in Altium Designer 13, enhanced in AD14.2, within their Schematic Editor.

GOST standards were originally developed by the government of the Soviet Union as part of its national standardization strategy. The word GOST is an acronym for gosudarstvennyy standart0, which means state standard or governmental standard.
Wikipedia GOST

↑  Page Index

graphene — A form of graphite, is particularly noteworthy for manufacturing electronics additively. Graphene is transparent, bendable, and offers high electric and thermal conductivity; these properties make it well suited to applications in integrated circuitry.28 However, the material has challenges: The process for extracting graphene from graphite can be expensive and complex, and supply of high-quality graphene can be inconsistent.
3D opportunity for electronics - Additive manufacturing powers ups.

↑  Page Index

GTL — Gunning Transceiver Logic is a type of logic signaling used to drive electronic backplane buses. It has a voltage swing between 0.4 volts and 1.2 volts-much lower than that used in TTL and CMOS logic.
Wikipedia https://en.wikipedia.org/wiki/Gunning_transceiver_logic

↑  Page Index

GTLP — Gunning Transceiver Logic Plus. Texas Instruments https://www.ti.com/pdfs/logic/gtlp.pdf

↑  Page Index

GUI — (GOO-ee)  Pronunciation Key  noun  [Software]  Graphical User Interface. It is a user interface that includes graphical elements, such as windows, icons and buttons. The term was created in the 1970s to distinguish graphical interfaces from text-based ones, such as command line interfaces. https://techterms.com/definition/gui

↑  Page Index

gull wing — [PCB Components] A narrow, flat lead that extends from the edge of an SMD downard and outward, and then flares outward at its end to form a foot, which is the solder contact point. (Contrast with J-lead.)

[Source: Circuit Technology Centre — 7.5.1 Soldering Surface Mount Gull Wing Components, Point To Point Method]

Gull-wing IC package leads are formed in a profile very similar to the outline of a seagull's wings. The gull wing is considered one of the most reliable terminations for fine-pitch, high pin-count packages. [Source: SURFACE MOUNT TECHNOLOGY (SMT) GULL-WING/"L" LEADED PACKAGES]

↑  Page Index