by John Walt Childers, IPC-CID, Founder of Golden Gate Graphics
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.
D code decal
destructive testing device DICY die
dielectric constant die paddle
digital circuit diode DIP DNI DNP DOS DOS-formatted double-track draw DRC
dry film solder mask DSP DUT
daisy chain (DAY-zee CHAYN) Pronunciation Key noun [Networking] A bus wiring scheme in which, for example, device A is wired to device B, device B is wired to device C, etc. The last device is normally wired to a resistor or terminator.
All devices may receive identical signals or, in contrast to a simple bus, each device in the chain may modify one or more signals before passing them on. daisy_chain_Howe_Denis_FOLDOC
DAP (DAP) Pronunciation Key noun [PCB Components] Die attach paddle. An exposed DAP (also called simply "EP" for "exposed paddle") provides a low thermal resistance between the die and the PCB to which the part is mounted and soldered. This allows rapid heat transfer from the die to the surrounding PCB copper traces, ground plane and air. Often this can be connected to ground and pierced with vias to more efficiently dissipate the heat straight into the ground plane.
On the PCB, vias should be placed in this exposed pad and connected to ground as an effective heat sink. Of course, if this die paddle is connected within the IC (integrated circuit) to some potential other than ground (rare), connect this pad and the vias to that potential instead of ground. If this die attached paddle is floating (not connected electrically to anything in the IC), the pad and the vias should be connected to ground. In PCB design layout of a DAP footprint, the solder paste artwork should not be one large rectangle: It should be several small rectangles. This prevents too large an amount of solder building up under the DAP and floating the package far enough off the PWB that some of the signal lands do not get solder, causing opens. See via and solder paste examples in Application Report - QFN/SON PCB Attachment, especially the topic "Solder Paste Screen Printing Process" and "Figure 11. Example Land Pattern and Exposed-Pad Stencil Design"
database A collection of interrelated data items stored together without unnecessary redundancy, to serve one or more applications.
D code Draft code. A datum in a Gerber file which acts as a command to a photoplotter. A D code in a Gerber file takes the form of a number prefixed by the letter D, e.g. "D20". However, in some aperture lists the D is dropped. In aperture lists of Cadstar, the column heading "Position" actually refers to D code, and the D prefix is dropped.
D codes have multiple purposes. The first is to control the state of the light being on or off. Valid codes for light state are D01, D02, and D03.
D codes with values of 10 or greater represent the aperture's position on the list or wheel. It is very important to understand that there is no universal "D10" or "D30". Unlike the D01 , D02, and D03 counterparts which have a fixed meaning ( draw , move, flash), D10 and higher values have aperture shapes and dimensions assigned to them by each individual user. Hence, one job's D10 could be a 10 mil Round, when another job's D10 could be a 45 mil Square.
There are two distinct ways to number an aperture list. The traditional 24 aperture system started with D10 - D19, jumping suddenly to D70 - D71, then back to D20 - D29, ending with D72 -D73. This is still a common format for output for CAD packages, and is still mandatory for old 24 aperture Gerber vector Photoplotters.
It is now common to start with D10, then increase numerically in steps of 1 (D10, D11, etc.) continuing up to D70 and beyond, rarely beyond 1000 individual apertures.
decal A graphic software representation of a component, so named because hand tape-up of printed circuit boards employed the use of pull-off and paste decals to represent components. Also called a part, footprint or package. On a manufactured board the body of a footprint is an epoxy-ink outline.
device Any type of electrical component on a PC board. It will have functions and properties unique to its type. In a schematic (and the extracted BOM ) , it will be labeled with a value or device number. There are two main classes of devices, passive and active.
die paddle (DAHY PAD-ə Pronunciation Key noun [PCB Components] (aka die attach paddle, or DAP) A thin plane of metal, within a packaged integrated circuit, to which a die is attached and which in turn is attached to a lead frame. Although adie paddle is internal to the IC package, it can be exposed on the bottom of the package in order to carry heat into the PCB, in which case a pad should be provided for soldering it to the PCB. If exposed, it typically carries no digital or analog signal but would usually be connected to ground. See also EP (Exposed Paddle).
On the PCB, vias should be placed in this exposed pad and connected to ground as an effective heat sink. Of course, if this die paddle is connected within the IC (integrated circuit) to some potential other than ground (rare), connect this pad and the vias to that potential instead of ground. If this die attached paddle is floating (not connected electrically to anything in the IC), the pad and the vias should be connected to ground. In PCB design layout of a DAP footprint, the solder paste artwork should not be one large rectangle: It should be several small rectangles. This prevents too large an amount of solder building up under the die paddle and floating the package far enough off the PWB that some of the signal lands do not get solder, causing opens. See via and solder paste examples in Application Report - QFN/SON PCB Attachment, especially the topic "Solder Paste Screen Printing Process" and "Figure 11. Example Land Pattern and Exposed-Pad Stencil Design"
differential signaling A method of signal transmission through two wires which always have opposite states. The signal data is the polarity difference between the wires: Whenever either is high, the other is low. Neither wire is grounded. [Graf]
For more information see the articles on this page:
Douglas Brooks Articles on Differential Traces
Or see an alternative viewpoint: Differential Signaling Doesn't Require Differential Impedance Or, How to Design a Differential Signaling Circuit, by Lee W. Ritchey
Regarding this alternative view: At Golden Gate Graphics we follow the advice of Douglas Brooks, not Lee W. Richey. Does that mean Ritchey is wrong? No. We adopt this policy of applying differential impedance design rules to our PCB layouts which have differential signaling, because it is the more conservative approach and is more likely to please our customers. It might also mean the boards manufactured to employ differential impedance control with testing via coupons and TDR will be more expensive. If the customer does not want this expense, that is their choice. If our layouts have incorporated differential impedance design rules, they will still work as well as a layout done without that control.
digital circuit A circuit which operates like a switch (it is either "on" or "off"), and can make logical decisions. It is used in computers or similar decision making equipment.
DIP Abbreviation for Dual In-line Package. A type of housing for integrated circuits. The standard form is a molded plastic container of varying lengths and 0.3 inch wide (although there are other standard widths), with two rows of through-hole pins spaced 0.1 inch between centers of adjacent pins.
DNP Do Not Populate. This acronym is often used on schematics to show that a component shown in the cirucit diagram is not actually placed and soldered on the finished printed circuit board during initial assembly. The footprint will be on the board, but no component will be there. This can allow an option for adding a component of that size and shape later for experimentation and debuggin.
DOS Disk Operating System. A program that controls the computer's transfer of data to and from a hard or floppy disk. Personal computers that are IBM-compatible run DOS rather than other early varieties of operating systems.
DOS-formatted (Of magnetic data storage media, such as floppy disks.) Prepared for storage of data in such a way that DOS transfer can occur.
DRC (DEE AR SEE) Pronunciation Key noun [Computer Aided Design] Design Rule Checking or Design Rule Check.
Design rules are set up in the PCB layout CAD file and include constraints related to shorts, opens, clearance, etc. A DRC is run to check for violations. The PCB designer can run this check periodically as a batch process on the entire design. With advanced layout software such as Altium Designer, the DRC can be set to automatic or "online:" A check is performed on-the-fly at any moment that the designer changes something and alerts him to any violation he may have just caused.
dry film solder mask A solder mask film applied to a printed board with photographic methods. This method can manage the higher resolution required for fine line design and surface mount. It is more expensive than liquid photoimageable solder mask.
DSP (DEE ES PEE) Pronunciation Key
DUT [Semi-conductor Manufacturing] Device Under Test. A DUT board (probe card) is used in automated testing of integrated circuits. It is part of the interface between the chip and a test head, which in turn attaches to computerized test equipment. The specific test equipment used will determine the value of the controlled impedance required for the chip tester boards. Depending on which system it is designed for, one type of DUT board is used in testing individual integrated circuits in a silicon wafer before they are cut free and packaged, and another type is used for testing packaged IC 's.
This is the best, most usable dictionary for electronics, because its
definitions help you grasp the terms and therefore the subject. Lesser
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jargon, leading one into endless "word chains." Not this one.
You can buy the Modern Dictionary of Electronics new or used via the Internet.
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: