A |
Ag.
Chemical symbol for element silver. |
Air Gap
- The shortest straight line air distance between two conductors
under voltage.
|
Annular Ring - The pad area that remains after a hole is drilled trough
the pad . |
Analog circuit - A circuit in which the output varies as a continuous function
of the Input.
|
ANSI - American
National Standards Institute. WWW page: http://www.ansi.org . |
AOI - Automatic
Optical Inspection. |
APERTURE - Aperture
list or D-Code assignment are used in defining shapes and sizes
of Gerber file entities.
|
ARRAY
- A sub-panel which include the multiple printed circuits (called
modules) so that the sub-panel can be assembled as a unit. The modules
can then be separated after assembly into discrete printed circuits. |
Aspect ratio -The ratio of the board thickness to the smallest-hole
diameter of the printed circuit board |
Assembly drawing - A drawing shows all parts identified by their reference
designator,anel outline with datum and tooling hole position. If
auto-insertion is required, a list of x, y coordinates of the parts
may be helpful. |
ATE
- Automatic Test Equipment |
Au -
Chemical symbol for element gold. |
AQL
- Acceptable Quality Level. |
Axial Component - An electronic
component consisting of two wire leads separated by a cylindrical
component body, e.g., resistors, diodes, capacitors. |
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B |
Bare board
- A finished PCB that has had no components added. |
BASE MATERIAL
- The insulating material upon which the conductor pattern may be
formed. The base material may be rigid of flexible - It may be a
dielectric sheet or insulated metal sheet. |
B&B
- Blind & Buried (VIA holes). |
BBT
- Bare Board Test. |
BGA
- Ball Grid Array. A leadless package on which the connectors to
the board have been placed in an array on the bottom of the package.
|
Blind VIA
- VIA hole that does not pass completely through the printed circuit
board. A blind VIA starts from one side or another. |
BOM
- Bill Of Material. A component list with reference designators,
part numbers, values, tolerance, description and other information.
A BOM is required for PCB assembly. |
BRIDGING(“SHORT”) - Solder that crosses the gap between two conductors,
such as two leads. |
Buried VIA
- A buried VIA connects two or more inner layers but no outer layer,
and cannot be seen from either side of the board. |
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C |
CAD
- Computer Aided Design. A system where engineers create a design
and see the proposed product in front of them on a graphics screen
or in the form of a computer printout or plot. In PCB manufacturing
the result would be a printed circuit layout. |
CAM -
Computer Aided Manufacturing. CAM files - these are the data files
used directly in the manufacture of printed wiring. |
CARD
- Another name for a printed circuit board. Card-edge Connector.
A connector which is fabricated as an integral portion of a printed
circuit board along part of its edge (see also finger). |
CBGA
- Ceramic Ball Grid Array. |
CEM
- Contract Electronic Manufacturers. |
CERAMIC
- Inorganic, nonmetallic material, such as alumina (a common substrate
material composed of approximately 95% Al2O3) or beryllia (BeO 99,5.
Beryllia has a high dielectric strength and a low dielectric constant)
. |
CHAMFER
- A shaped corner to eliminate an otherwise sharp edge. |
Characteristic Impedance - A compound measurement of the resistance, inductance,
conductance and capacitance of a transmission line expressed in
ohms. |
CHIP
- Non polarized surface mount capacitor, resistor or inductor with
tinned conductive solder terminals at opposite ends of the part. |
CLAD
- A copper object on a printed circuit board. |
Clearance
- Separation between circuit entities ( pad-pad, pad-trace, trace-trace,
solder mask-pad, pad-drill, circuit-board edge, etc.). |
Coefficient of Thermal Expansion
(CTE) - The ratio of dimensional change
of an object to the original dimension when temperature changes. |
COFIRE - A process for forming multilayer ceramic substrates
in which thick-film conductors and dielectrics are simultaneously
processed by a firing cycle. |
Column Grid Array (CGA) - A packaging technology similar to a pin grid array,
in which a device`s external connections are arranged as an array
of conducting pins on the base of the package. |
Compliant pin
- The forces required for a good contact between pin and through
hole are generated by the deformation of the press-fit section of
the pin |
COMPONENT
- Any of the basic parts used in building electronic equipment,
such as a IC, transistor, resistor, capacitor, connector, etc. |
Conductor Spacing - The distance between tracks on a printed circuit board. |
Conductor width - The observable width of the pertinent conductor at
any point chosen at random on the printed circuit board. |
CONNECTION
- One leg of a net . Also called a "pin pair." |
CONNECTOR
- A plug or receptacle which can be easily joined to or separated
from its mate. |
Contact resistance - The resistance which occurs at the point of contact
between a female contact and the male connector pin. |
Controlled Impedance - The process that give a circuit the correct impedance
value. |
Copper foil
- Quality electrolytic copper used to form conductive patterns on
printed circuits. The traditional weights are 0.5, 1 and 2
ounces per square foot (18, 35 and 70 micrometer thick) |
Copper thickness - Cooper thickness usually specified in terms of number
of Oz/sq. ft (1/2 Oz: 17.5um; 1 Oz: 35um and etc.). The thickness
of copper you specified will be the final thickness of base material
plus copper plating thickness. |
CSP
- Chip Size/Scale Packag.e |
CTE -
Coefficient of Thermal Expansion. |
Cu -
Chemical symbol for element copper. |
Cut lines
- A cut line is what we are going to use to program a router with.
It represents the outer dimensions of board. |
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D |
DFSM
- Dry Film Solder Mask. |
DIELECTRIC
- An insulating medium which occupies the region between the conductors.
It is also the distance between bonded inner layer conductors.
|
Dielectric Constant - That property of a dielectric that determines the electrostatic
energy per unit volume for unit potential grade. |
DIP
- Dual In-line Package . A package designed for through hole mounting
with parallel rows of evenly spaced leads extending straight down
below the package at right angles to the top and bottom surfaces. |
Drill File
- Usually this is an Excellon file (with X and Y axis
coordinates and tool sizes) used to create the hole of a circuit
board. |
Drill Table
- A description of the drill sizes used to create the circuit board.
The drill equivalent of an aperture list. |
Dry Film Solder Mask (Resist) - 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. |
Dummy Component - A non-functional component package. |
Dummy Land -
A conductor on a printed circuit board that is not connected electrically
to other circuitry. |
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E |
Edge Connector - A connector (can be gold plated) edge contacts or a
series of parallel lines of holes.
|
Electrical Test - Used to test for opens and shorts. Recommended for
all surface mount boards and multi-layers. Traditional test are
done by test fixture with test pins wired to test system and compare
connections/insulation read from board to board, an efficient type
of test for volume production. Another type of test namely
the flaying probes test, a set of 2 probes (or two sets, one set
at top of board and another set at bottom), moving quickly to verify
connectivity against the Netlist generated from Gerber or other
CAD/CAM data. |
Electroless Nickel Immersion Gold - A coating applied during printed circuit board manufacture
to protect copper features from oxidation and provide a very flat
surface for soldering components. |
Electromagnetic Compatibility
(EMC) - (1) The ability of electronic
equipment to operate in an intended electromagnetic environment
without degradation caused by interference. (2) The ability of equipment
to operate in its electromagnetic environment without creating interference
with other equipment. |
ELECTROPLATING - The electrode position of a metal coating on a conductive
object. The object to be plated is placed in an electrolyte and
connected to the relative terminal of a DC voltage source. The metal
to be deposited is similarly immersed and connected to the positive
terminal. Ions of the metal provide transfer to metal as they make
up the current flow between the electrodes. |
Epoxy Resin -
A material that forms straight chain thermoplastic and thermosetting
resins. Epoxy resins have excellent mechanical properties
and good dimensional stability |
ETCHING -
The process of removing unwanted metallic substance (bounded to
a base) via chemical, or chemical and electrolytic means. |
Etch factor
- The ratio of the depth of etch (conductor thickness) to the amount
of lateral etch (undercut). |
ESR - Electrostatically applied Solder
Resist. |
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F |
Fiducial mark
- Fiducial marks are dots etched on board panel for which SMD assembly
is required (provide viewing targets for camera to locate correct
position). |
FILLET
- Refers to the shape of the solder joint between the lead and the
pad. Visual inspection criteria are largely based on the size and
the shape of the fillet. |
Fine pitch
- Component with lead pitch equal to or greater than 20 and less
than 50 mils; most common pitches are 20, 25, 33 mil. |
FINGER
- A terminal (usual –gold plated) of a card-edge connector. |
FIXTURE
- A device that enables interfacing a printed circuit board with
a spring-contact probe test pattern. |
Flex circuit (Flexible circuit)
- A printed circuit made of thin, flexible
material. |
FLUX -
A substance used to promote or facilitate fusion, such as a material
used to remove oxides from surfaces to be joined by soldering welding.
Flux types: low residue, organic acid, rosin, rosin activated, rosin
mildly activated. |
FR4
- Flame retardant laminate made from woven glass fibre material
impregnated with epoxy resin. |
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G |
Gerber File
- Data file used to control a photoplotter. Named after Gerber Scientific
Co., who made the original vector Photoplotter. |
Gold Finger -
The gold-plated terminal of a card-edge connector. |
Ground Plane
- A relatively large mass of metal on a printed circuit board used
as an electrical ground or shield. |
Grid Spacing
- This is the spacing between drilled through holes in a printed
circuit card. |
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H |
HDI
- High Density Interconnection. |
HTCC
- High Temperature Cofired Ceramics |
Hole breakout
- A condition in which a hole is not completely surrounded by the
land. |
Hole density
- The quantity of holes in a printed circuit board per unit area
. |
Hole void
- A void in the metallic deposit of a plated - through hole exposing
the base material. |
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I |
IEEE
- Institute of Electrical and Electronic Engineers. IEEE Standards
Board, New Jersey, USA. WWW page: http//www.ieee.org. |
IEC
- International Electrotechnical Commission is the leading global
organization that prepares and publishes international standards
for all electrical, electronic and related technologies. These serve
as a basis for national standardization and as references when drafting
international tenders and contracts. www-page : http://www.iec.ch |
INCH
- One inch = 25,4 mm. |
INK
- Common term for screen resist. |
Insulation Resistance - Resistance of the insulating part between two conductors.
|
INTEGRATED CIRCUIT (IC) - An assembly of miniature electronic components simultaneously
produced in batch processing, on or within a single substrate to
perform an electronic circuit function. |
Internal layer
- A conductive pattern which is contained entirely within a multi-layer
printed board. |
Interstitial via hole - A plated through hole connecting two or more conductor
layers of a multi-layer printed board but not extending fully through
all of the layers of base material comprising the board. |
IPC
- .The Institute for Interconnecting and Packaging Electronic Circuits.
WWW page: http://www.ipc.org . |
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J |
JUMPER
- An electrical connection formed by wire between two points on
a printed board added after the intended conductive pattern is formed. |
L |
LAND
- A portion of a conductive pattern that is usually used for making
electrical connections or for component attachment, or both. |
LEAD
- Metal attachment on a component used to mount the component to
a printed circuit board and establish an electrical pathway. |
LEGEND
- A format of lettering or symbols on the printed board :
part number, component locations, and patterns. |
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. |
LTCC
- Low Temperature Cofired Ceramics. |
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M |
MASTER DRAWING - A document that shows the dimensional limits or grid
locations applicable to any or all parts of a printed board (rigid
of flexible), including the arrangement of conductive and nonconductive
patterns or elements. |
Metal-Core PCB - Boards built with a metallic core and an organic or inorganic
insulation on either sides of the core. The core could be made of
steel, stainless steel, aluminum, copper, or a laminate of metals. |
MIL
- One thousandth of an inch. |
Minimum Annular Ring (MAR) - The minimum metal width, at the narrowest point between
the circumference of the hole and the outer circumference of the
land. |
Minimum Conductor Width - The smallest width of any conductors, such as traces,
on a PCB. |
Minimum Conductor Space - The smallest distance between any two adjacent conductors,
such as traces, in a PCB. |
Multi-layer PCB (ML) - Printed circuit boards consisting three or more conducting
circuit plans separated by insulating material and bonded together
with internal and external connections to of the circuitry as required. |
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N |
NC Drill
- Numeric Control drill machine. A machine used to drill the holes
in a printed board at exact locations, which are specified in a
data file.
|
NC Drill File
- A text file which tells an NC drill where to drill its holes. |
NetList
- List of names of symbols or parts and their connections points
which are logically connected in each net of a circuit. |
NFP
- Non functional pad. |
NFL
- Non functional land. A land on internal or external layers, not
connected to the conductive pattern on its layer. |
Ni -
Chemical symbol for the element nickel. |
NPTH
- Non plated-trough hole . |
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O |
OEM - Orginal Electronic Manufacturers. |
OSP - Organic Solderable Preservative. |
OVERHAND
- Increase in printed circuit conductor width caused by plating
build-up or by undercutting during etching. |
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P |
PAD (LAND)
- The portion of the conductive pattern on printed circuits designed
form the mounting or attachment of components. |
PANEL
- Material sized for fabrication of printed circuit boards. For
example, standard panels by many Korean manufacturers are 340 x
407mm, 407x 510 mm, 510x 610 mm.
|
PANELIZE -
1.To lay up more than one (usually identical)printed circuits on
a panel. Individual printed circuits on a panel need a margin between
them of 3-7 mm. 2. Lay up multiple printed circuits (called modules)
into a sub-panel (array) so that the sub-panel can be assembled
as a unit. The modules can then be separated after assembly into
discrete printed circuits. |
PATTERN
- The configuration of conductive and non-conductive materials on
a panel or printed board. Also the circuit configuration on related
tools, drawings, and masters. |
Pb -
Chemical symbol for element lead. |
PCB -
Printed circuit board. |
Plated-through Hole (PTH) - A hole in a PCB with metal plating added after it is
drilled. Its purpose it to serve either as a contact point for a
through-hole component or as a via. |
Press-fit Connection - The press-fit connection which is made of elastic deformable
or massive (solid) pins into the plated through holes of the PCB.
At the point of contact between the pin and the through hole plating
a gas tight connection ensues. |
Press-fit Pin
- A metal pin with a specified area for pressing into a plated through
hole without the requirement of further soldering. There are two
types of press-fit pins : solid and compliant pins. |
Printed Circuit Board (PCB) - A flat plate or base of insulating material containing
a pattern of conducting material. It becomes an electrical circuit
when components are attached and soldered to it. The conducting
material is commonly copper which has been coated with solder or
plated with tin or tin-lead alloy. The usual insulating material
is epoxy laminate |
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R |
Radial Component - An electronic component with two or three wire leads
emanating from the component body that is designed to stand up on
the PCB by its leads, e.g., transistors, capacitors, hairpin axial
components, etc. |
REGISTRATION
- The degree of conformity of the position of a pattern, or a portion
thereof, with its intended position or with that of any other conductor
layer of a board.
|
RESIST (Solder Resist) - A coating material that is used to mask or protect
selected areas of a circuit board from etching or plating processes. |
ROUTING
- In PCB CAD layout application, routing refer to as making manual/automatic
wiring connecting logical nodes in a net. In PCB fabrication, routing
refers to board edges profiling by running N-C program. |
RS-274-D -
Photoplotter file format (a variant of Gerber data) requiring an
additional aperture information file. |
RS-274-X.
- A variant of Gerber data which contains aperture shape information
in addition to the usual tool selection and movement commands. |
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S |
Schematic Diagram - A drawing which shows, by means of graphic symbols,
the electrical connections, components, and functions of an electronic
circuit. |
SCP
- Single Chip Package |
SHORT
- Short circuit. An abnormal connection of relatively low resistance
between two points of a circuit. |
Silk-screen
- The decals and reference designators in epoxy ink on a printed
wiring board, so called because of the method of application - the
ink is squeegeed through a silk screen. |
SMC
- Surface Mount Component. |
SMD
- Surface Mount Device. |
SMT
- Surface Mount Technology. |
SMOBC -
Solder mask over Bare Copper. |
Sn -
Chemical symbol for element tin. |
SOLDER
- Metal alloy used in soldering containing one of the metals used
in the formation of an intermetallic bond. |
Solder Balls - Small balls of solder that blow or roll across circuit
boards causing shorts and other mischief. |
Solder Levelling - The process of immersing printed circuit boards into hot
liquids. Often referred to as HASL or HAL (hot air levelling) |
Solder Mask
- A coating applied over selected areas of a circuit board thereby
permitting soldering only of the exposed areas : the contacts to
be soldered; the gold-plated terminals of any card-edge connectors
and fiducial marks. |
Solder paste
- Form of solder to be printed on SMD pads by using a stencil in
assembly. |
Solderability Testing - The evaluation of a metal to determine its ability
to be wetted by solder. |
Solid pin
- The forces required for a solid mechanical contact between pin
and hole are generated by the deformation of the drilled through
hole. |
SPAN
- Component span refers to the center to center lead spacing of
axial and radial components. |
STENCIL
- Stencil is a cooper foil screen with SMD pads etched openings
use for solder paste printing in assembly. |
Sub-panel - A group of printed circuits
(called modules) arrayed in a panel and handled by both the board
house and the assembly house as though it were a single printed
wiring board. The sub-panel is usually prepared at the board house
by routing most of the material separating individual modules, leaving
small tabs. |
SUPPORTED HOLE - A hole in a printed board that has its inside surface
plated or otherwise reinforced. |
SUPPORTING PLANE - A planar structure that is a part of a packaging and
interconnecting structure to provide mechanical support, thermo-mechanical
constraint, thermal conduction and/or electrical characteristics. |
Surface Mount - Surface mount technology (SMT) - The technology of creating
printed wiring wherein components are soldered to the board without
using holes. |
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T |
TAB
- Tape Automated Bonding.
|
Tented VIA
- A VIA with dry film solder mask completely covering both its pad
and its plated-through hole. |
Test Coupon
- An area of patterns on the same fabrication panel as the PCB,
but separate from the electrical circuits and outside the actual
board outline. |
Tg -
Glass transition temperature, temperature at which substrate changes
from hard to soft. |
Through-hole
- Having pins designed to be inserted into holes and soldered to
pads on a printed board. |
Tooling Hole -
A hole in a PCB that has close tolerances for hole diameter and
accurate location in relation to the component insertion holes. |
Tooling Pin
- A pin on a workboard holder that holds the PCB in proper position
by closely fitting into a tooling hole. |
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U |
UL -
Underwriter`s Laboratories, Inc. - supported by some underwriters
for the purpose of establishing safety standards on types of equipment
or components. WWW page : http://www.ul.com . |
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V |
V-cut scoring - This is a V-shaped cut made between boards within an
array.. This process is used when boards are placed side-by-side
within the array with zero spacing between boards. After assembly
the boards are snapped apart along the V-cut. |
VIA
- Feed-through. A plated-through hole in a PCB used to route a trace
vertically in the board, that is, from one layer to another. Common
type of via connects traces on all layers, blind via or buried via
are connected to defined layers only. |
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W |
Warping
- Warping generally refer to finished board warp and twist. All
boards may have certain degree of warp as result of manufacturing,
specially if materials contains high volume of moisture. |
Wet Solder Mask - Applied by means of distributing wet epoxy ink through
a silk screen, a wet solder mask has a resolution suitable for single-track
design, but is not accurate enough for fine-line design. |
Wetting
- Ability of a liquid to flow across a surface as opposed to sticking
to itself. Wetting occurs when the attractive surface energy of
the pad or lead is greater than the surface energy of the solder,
drawing a molecularly thin layer of solder across itself. |
Wicking
- Ability of solder to travel towards a heat source or fill a through-hole.
|
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X |
X Axis - The horizontal or left-to-right
direction perpendicular to the Y axis in a two-dimensional system
of coordinates. |
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Y |
Y Axis - The vertical direction,
perpendicular to the X axis, in a two-dimensional system of coordinates. |
