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28 IEEE Spectrum | October 2006 | NA www.spectrum.ieee.org
illustrations by john ueland
W
hen you live on the cutting edge of technology, so to speak. We contacted several newly minted IEEE Fellows,
there are, literally, no words to describe it. Instead we whose experiences prove the point.
have acronyms. Lots and lots of acronyms.
Sandra Johnson, chief technology officer for IBM’s global
And for good reason. Imagine a discussion of high-density- small and medium businesses, recalls attending a presentation
technique metal-oxide semiconductors, integrated database that was so chock full of esoteric acronyms that she “leaned
application programming interfaces, or—let’s go out on a limb over to the people next to [her] and asked if they knew what
here—separate absorption-graded multiplication avalanche photo­ the presenter was talking about, and they didn’t,” she says.
diodes. Without acronyms, by the time you got halfway through Johnson’s question got all the way around the room, but no one
the conversation, the technology in question would be obsolete.
was familiar with all of the acronyms the presenter was using.
Here we’ve compiled a list of our favorites to help you through “It was amusing,” she says. “This guy was going to town, and no
your day. It’s not meant to be comprehensive—there are plenty of one knew what he was talking about.”
more thorough sources, including an IEEE dictionary—and it’s cer“Certainly I’ve been lost,” says Charles J. Alpert, technical lead
tainly not meant to be offensive. But we hope it shows the interest- for design tools, at IBM’s Austin (Texas) Research Laboratory.
ing and sometimes really weird ways new acronyms come about. “Especially the first year I was at IBM. I’m embarrassed. I’m new.
Don’t feel bad if many of these terms are new to you. It has But I realized I might as well interrupt people when they’d use
gotten to the point where even the luminaries are in the dark, acronyms I didn’t know and ask.”
That’s Waguih Ishak’s philosophy, too. “I think it’s actually
sometimes insulting to assume people know these acronyms,”
says the vice president and chief technology officer of chip maker
Avago Technologies, in San Jose. He recalls a corporate technology review at HP in 1996. Intrigued by the volume of acronyms
he heard during the very first presentations, he began writing
them down. Ishak was scheduled as the penultimate speaker,
but after the barrage of scholarly papers, he realized everyone
was exhausted. So he scrapped his presentation and instead
announced: “I’m going straight to the glossary.” He’d compiled
seven slides’ worth of acronyms in just two days.
T
he vast majority of what we commonly call acronyms
are really another type of abbreviation: an initialism.
Technically an initialism becomes an acronym only if
pronounceable as a word—radar (radio detection and ranging)
or BASIC (Beginner’s All-purpose Symbolic Instruction Code),
for example. On the other hand, people have found ways to pronounce the ostensibly unpronounceable, and thus SCSI (small
computer system interface) became “scuzzy.” More recently,
some of the folks involved in the wireless metropolitan area
network (WMAN) field have publicly wondered if it was a good
idea to pronounce that acronym “woman.”
Engineers, who tend to be adamant about technical standards
and specifications, are pretty ambivalent about consistent capitalization. Thus we end up with the indecisive VoIP (voice over
Internet Protocol) and QoS (quality of service). To say nothing of
MIPS and MOSFET, which, rendered entirely in capital letters,
are like little printed screams.
Some acronyms become like talismans—kept and frequently
used long after the exact meaning has faded. IBM’s Alpert says
he once attended a “Jeopardy”-like game held for a gathering
of 300 design engineers. “One category was acronyms. We all
recognized them, but nobody knew what they were. We’d used
them for so long we’d forgotten what they stood for,” he says.
The classic example is laser. Though countless people use
lasers every day, most nontechies have no idea the word is an
acronym for light amplification by stimulated emission of radiation. Laser’s place in language has so evolved that it has even
spawned a verb: “to lase.”
Some lexicographic wit coined a term for what’s ­happened
to laser, radar, and their ilk: they’ve become ­a nacronyms,
a ­neologism that smooshes the sounds (and the meanings) of
acronym and anachronism. The product of smooshing two words
together, by the way, is a portmanteau.
When an acronym becomes an anacronym, funny things can
happen to it. For one, people sometimes start saying the acronym
coupled with the verbalization of one of its constituent elements.
Hence in “SCSI interface,” the word “interface” is completely
redundant, because that’s what the “I” is for.
Another linguistic mind-bender is the creation of matryoshka
acronyms—acronyms that, like Russian nesting dolls, when opened
are found to contain other abbreviations inside. Our favorite: ABT,
Advanced BiCMOS Technology, with the acronym BiCMOS right
in the middle. True, BiCMOS isn’t exactly an acronym; it’s more
of a portmanteau of bipolar and CMOS (complementary metal
oxide semiconductor), but you get the idea.
U
sing the 26-letter English alphabet, the number
of possible three-letter acronyms is 17 576. And yet the
potential afforded by this sizable number is apparently
insufficient for engineers and technology hawkers who can’t
seem to avoid reusing abbreviations.
www.spectrum.ieee.org Take, for example, ATM. It is asynchronous transfer mode,
automated teller machine, and Adobe Type Manager. What we love
about ATM is that even engineers don’t know which ATM anyone
is talking about without contextual clues. It is the same with
DLL (dynamic link library and delay-locked loop) and SPI (SCSI
parallel interface, serial peripheral interface, stateful packet
inspection, and system packet interface). And then, of course,
there’s PC: printed circuit, personal computer, program counter,
and, oddly enough, “carrier power” of a radio transmitter.
Though we can’t help you tell whether someone is talking about
CMOS or sea moss, we think we can broaden your ­knowledge
of the industry lingo. So for your delectation, we’ve compiled
a banquet of some of our favorite recent electronics acronyms
and initialisms. Find your favorites or see how many you know.
If you’ve had an amusing encounter with an abbreviation or
know the odd secret history of an acronym, drop us a line.
The Glossary
ABT Advanced BiCMOS technology. Building BiCMOS chips,
which combine bipolar transistors and field-effect transistors,
started out as a fairly complicated process; apparently it’s
become even more so.
AJAX Asynchronous JavaScript and XML. A programming
approach combining the constituent technologies in the acronym, intended to make Web pages feel more responsive. It lets
a server load new content onto an open Web page without the
browser’s having to reload the whole page.
BEOL Back end of line. The BEOL and end-all of acronyms. (It’s
a pun. No, it’s not really funny. Puns never are.) Refers to latterstage processes in IC production, including interconnecting the
devices on the chip. It’s the opposite of front end of line (FEOL),
where sexier stuff, like making transistors, happens.
CSP Chip-scale package. A sure sign that some people in
the electronics industry are underemployed is that they keep
inventing new abbreviations for things that already have a
perfectly functional one. Case in point: CSP is for all intents
and purposes just BGA (ball-grid array). That’s where you place
a chip onto a substrate of the same size that has an array of
solder balls beneath it. Then you put that assemblage onto a
printed circuit board and melt the balls to link the chip to
the circuit board’s wiring. W-CSP (wafer-level CSP) is actually something new. In W-CSP you build the package with
its solder balls onto the chip even before it’s been cut out of
the wafer.
DFM design for manufacturability. A design approach that
recognizes the seemingly obvious idea that if it’s hard to build,
it’s not a good design. In IC manufacturing, DFM takes into
account things like whether your newly designed circuit is in
danger of being accidentally scrubbed away during important
wafer-smoothing steps.
DMD digital micromirror device. An array of tiny movable mirrors on a chip. Developers at Texas Instruments (TI)
originally thought DMDs might usher in an age of ­highfalutin
optical computing, but instead DMDs are found mostly in rear­projection TVs (RPTVs) showing low-brow programming and
October 2006 | IEEE Spectrum | NA 29
in projectors showing boring PowerPoint presentations. In both
cases a DMD steers light onto the screen to form an image.
ESL electronic system level. Modifies the word “tools.” ESL
tools, still in the process of being defined, are circuit designautomation software that handles things like the integration
of hardware and software—a problem barely acknowledged by
current design-automation systems.
FBAR film bulk acoustic resonator. A type of piezoelectric
filter that has allowed cellphone makers to greatly shrink the
size of handsets. It replaced another type of filter made from
ceramic materials, which was, for a time, one of the bulkiest
components in a phone.
FeFET ferroelectric field-effect transistor. Imagine a nonvolatile memory that operates at low voltages, stores and disgorges data in mere nanoseconds, and doesn’t destroy the data
in order to read it, as some other memory technologies do. You
just got all tingly, didn’t you? We thought so. You’d need a functional FeFET to make such a memory. It’s a type of transistor that
stores data in a layer of ferroelectric material—stuff that, once
polarized by a voltage, stays polarized even after the voltage is
gone. For a number of reasons, these transistors aren’t ready for
commercialization.
GaN-on-SOD gallium nitride–on–silicon on diamond. It’s
really hard to make a decent-size wafer of gallium nitride; so
people are always trying to build GaN devices on top of other
stuff. GaN-on-SOD takes that approach to the extreme. SOD
is not to be confused with its evil twin, DOS (diamond on
silicon), which has absolutely nothing to do with a PC’s disk
operating system.
GMR giant magnetoresistor. A spintronic device using the
giant magnetoresistive effect. Spintronics is a relatively
new endeavor involving nanoelectronic devices that make
use of electron spin rather than charge. In a GMR device,
a magnetic field produces a change in the resistance of a
­n anometers-thick conductive layer. The devices make good
magnetic switches that are so reliable some implanted defibrillators now incorporate them. The effect is commonly used
by hard drive read heads.
IP Internet Protocol; intellectual property. The first is the
communications protocol that makes the World Wide Web go
round; the second describes a reason to end up in court. IP is
distinguishable only in context and is a particularly pernicious
reuse, in that you could easily have a single conversation that
includes references to both.
LCOS liquid crystal on silicon. A display technology used
in some RPTVs (see DMD), in which a layer of liquid crystals
is bonded to and controlled by a dense array of transistors on a
silicon chip. The liquid crystal can either reflect or block light
depending on the voltage at the transistor, thus forming an
image. In an RPTV, a bright light reflects off one or more of the
chips and projects a magnified image onto the TV screen.
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30 IEEE Spectrum | October 2006 | NA LOC lab on a chip. A miniature chemical analysis system built
on silicon chips or at least built using chip-manufacturing techniques. Often they include micrometer-scale pumps, valves, and
flow sensors. They should be good for on-the-spot chemical
analysis, environmental monitoring, medical diagnostics, and
other things. Fans of Greek lettering call it a µTAS (micro total
analysis system).
LSA laser spike annealing. A step in building advanced microchips that prevents current from leaking in nanometer-scale
transistors. Basically, it zaps the chip, while it’s still part of a
silicon wafer, with a laser, heating it to 1300 °C and fixing defects
in its transistors. LSA is not to be confused with latent semantic analysis, a very different technology that lets a computer
study a textbook and then pass a multiple-choice exam about
the material in it.
LTPS low-temperature polycrystalline silicon. A material found at the edges of some new liquid-crystal display
(LCD) TVs. The transistors that control the individual pixels
of an LCD are made of amorphous silicon, a version with no
crystalline structure. Baking amorphous silicon—the high­temperature approach—makes it polycrystalline silicon, or
polysilicon, a more crystalline version that makes for faster
transistors. LTPS is a more practical idea wherein you crys-
www.spectrum.ieee.org
MRAM magnetoresistive (or magnetic) random access
­ emory. A newly commercialized nonvolatile memory device
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that uses electron spin, which is related to magnetism, to store
data. It combines some of the best attributes of other types
of commercial memory technologies, except, at the moment,
their low price.
NEMS nanoelectromechanical system. A chip with moving
parts, or one with parts through which something other than
electric current moves. They used to be microelectromechanical
systems (MEMS), but they’ve been on a diet.
PDS placement-driven synthesis. A design method that lets
you specify the behavior of a block of circuitry and translates
that into a detailed circuit plan, right down to the size of the
parts of the individual transistors. It uses a bunch of nifty techniques, including placement, which figures out the best route
for the circuit’s wiring to minimize how long it takes a signal
to get where it needs to go on the chip.
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tallize the amorphous silicon by blasting it with a laser. LCD
makers use LTPS to form circuits at the edges of the display
to better control the pixels. Thus, LTPS is destined to become
a term misused by marketers to confuse consumers shopping
for large-screen high-­definition TVs.
MHEMT metamorphic high-electron-mobility transistor.
An MHEMT is a variation of a high-electron-mobility transistor (HEMT), which is a type of really fast switch. It’s made by
putting a layer of material between two semiconductors whose
crystal structures are different enough that they otherwise
would not get along. Among other applications, MHEMTs are
found in adaptive cruise-control radar in cars you probably cannot afford.
PECL positive emitter-coupled logic. A way of constructing
logic circuits so that they operate faster, but at the expense
of continuously draining power. PECL is just ECL operated
between positive voltage and ground, in contrast to negative
voltage and ground. Another ECL variation is LVPECL (which
we dearly wish were pronounced “love peckle”), or low-voltage
PECL, a PECL powered from a 3.3-volt power supply. Though
CMOS is the logic circuit technology of choice these days,
PECLs can still be found transmitting clock signals on chips
and sending data down the bus in computers.
QDIP quantum-dot infrared photodetector. An IR detector
noted for its high temporal resolution and low noise-equivalent
temperature difference (NETD), which is a measure of sensitivity. That would seem to make QDIPs good for use in nightvision goggles and other cool stuff, except that they have to be
frozen to work well.
RAS reusable asset specification. The recycling rules for
software engineering. It defines a standard way to package pieces
of code so that they can easily be reused. RAS is part of a movement in software design called asset-based development (ABD),
in which you keep software reuse in mind as you build a system.
Elsewhere RAS means reliability, availability, serviceability,
a perfectly sensible set of system performance parameters.
MIPS millions of instructions per second. A measure of computer performance—aka meaningless information provided by
salesperson. Also microprocessor without interlocked pipeline stages, a chip architecture developed by MIPS Technologies.
You might conceivably ask a salesperson from MIPS how many
MIPS his MIPS chip does.
SED surface-conduction electron-emitter display. That
should be SCEED, right? We thought so. Normally we disdain cheating, but on the other hand we admire the chutzpah
required to simply discard 40 percent of your word count to
get to a marketable acronym. SEDs are flat-panel displays
where each pixel in the display is like a miniature cathoderay tube. They’re said to have the brightness and contrast of
CRTs but to use one-third less power than plasma TVs. The
developers are having a devil of a time commercializing SEDs,
by the way. SEDs are similar to field-emission displays (FEDs),
which you can’t buy yet either.
MPSOC multi-processor system on a chip. An SOC (system
on a chip) integrates all the components of an electronic gizmo
on a single chip. Reflecting a general trend in the microprocessor business, an MPSOC ups the ante by integrating multiple
processors onto the same chip.
SIMOX separation by implantation of oxygen. A means of
producing SOI (silicon-on-insulator) wafers. First you implant
oxygen beneath the surface of a silicon wafer. Then you cook
the wafer until an insulating oxide layer forms beneath the
surface of the silicon. Besides making attractive trivets, SOI
www.spectrum.ieee.org October 2006 | IEEE Spectrum | NA 31
The SO Family
The letters S and O have lately become
a dizzyingly fecund breeding ground of
jargon. Here’s the family tree.
SOI Silicon on insulator. A type of silicon wafer that improves
the speed and power consumption of CMOS circuits. It involves
making a thin layer of insulator, usually silicon dioxide, buried
up to 100 micrometers below the surface. The insulation layer
reduces the amount of charge the transistor needs to move in
order to switch, and it blocks leaking current. AMD uses lots of
SOI; Intel, not so much.
SOS Silicon on sapphire. Silicon on insulator (see SOI) by
other means. In SOS you deposit a thin layer of crystalline silicon
atop a wafer of sapphire—otherwise known by its less bejeweled
name, aluminum oxide. SOS circuits are usually found in space
chemical (see SOD for how that works). And finally, SOG is
sometimes sea of gates, a way of minimizing the work of chip
construction. A sea-of-gates approach assumes lots of different
chips can start out as just a vast grid, or “sea,” of logic gates.
The only difference between the chips is in how you wire the
gates to each other.
SOA Silicon on anything. In SOA, a favorite of Philips
Electronics, you build a circuit on a silicon wafer, then chemically dissolve away almost the entire wafer, starting from the
back side, so that only the part containing the circuitry is left.
Finally, you glue this sliver of circuits to “anything.” In practice,
“anything” seems to mean glass (see SOG). The glass-silicon
combination lets you integrate RF components such as inductors onto the chip. On ordinary silicon chips, integrating inductors is difficult to do, because the silicon tends to soak up the
inductor’s signal.
S ON Si l i co n o n n ot h i n g. Ta k i n g t h e
s­ ilicon-on-insulator concept to the extreme,
­researchers—mostly at STMicroelectronics—
are experimenting with transistors suspended
over small pockets of air, one of the best insulators around.
SOIC Small-outline IC. A rectangular plastic
chip package that has connecting pins that stick
out from the side in a so-called gull-wing configuration. That is, the pins stick out, then turn
down, and then go out again.
and military systems, because the sapphire keeps stray currents
caused by radiation from messing with the silicon circuits.
SOAN Silicon on aluminum nitride. A new version of silicon
on insulator (see SOI) where you build a silicon wafer with a
thin, electrically insulating layer of aluminum nitride buried just
below the surface. The aluminum nitride gives electrical benefits
similar to those of SOI’s usual insulator, silicon dioxide, but it’s
better at drawing heat away from the circuits.
SOG Silicon on glass, spin-on glass, sea of gates. In general, SOG is some form of silicon on a substrate of glass. From
there, things get complicated. The silicon in question could
be polycrystalline, the type found at the edges of newer LCD
­panels, where manufacturers are building an increasing amount
of circuitry right onto the panel. Or SOG could refer to crystalline silicon that is patterned into a circuit and then bonded to
glass. SOG can also mean spin-on glass, a way of applying a
thin layer of silicon dioxide insulation to chips using a liquid
32 IEEE Spectrum | October 2006 | NA SOD Spin-on deposition. A method of applying a layer of material to a semiconductor wafer.
The wafer is spun like a record, and a liquid
is poured onto the center. The wafer’s rotation draws the liquid out from the center, so it
forms a layer of uniform thickness across the
surface. SOD is the method you’d use to apply a
spin‑on dielectric, a material used to insulate
the on‑chip wiring on some ICs.
SOM Sulfuric acid–ozone mixture. We bet you thought this
was silicon on manganese oxide or some other crystal. But no!
It’s actually a nasty chemical brew used to scrub silicon wafers
clean in between chip processing steps.
SOC System on a chip. An IC that packs a microprocessor,
memory, timers, voltage regulators, and all the other stuff
you’d need to build a computer or another electronic system.
The reconfigurable version of the chip is, predictably, called a
system on a programmable chip, or SOPC.
SOP System on package. Can’t fit your system on a chip?
Make it on separate chips and put them in the same package.
And integrate all the capacitors and other components into the
package while you’re at it. It’s often confused with system in
package (SIP). SIP predates SOP and tends not to squeeze in
quite so much non-IC stuff.
www.spectrum.ieee.org
wafers let transistors run faster and consume less power,
because the insulation layer reduces the amount of charge
the transistor needs to move in order to switch and it blocks
leaking current.
STRIFE stress plus life (testing). A portmanteau posing as an
acronym—there’s no reason for this word to be in all capital letters other than the perversity of whoever minted it. We’re fond
of it anyway, because it actually means what it says.
TCAM ternary content-addressable memory. Say you are
looking for the letter Q in a computer memory. If the memory is
plain old random-access memory (RAM), you have to check each
address one at a time to see if the binary equivalent, 01010001, is
hiding there. The same process in a CAM is much faster because
it lets you look for a match by reading the entire contents of the
memory all at once. CAM is great for things like Internet packet
routing and pattern recognition. TCAM takes it to another level
by letting you search for 010100XX—or P, Q, R, and S—at the
same time.
TLA What do the following have in common? ATM, VCR, IBM,
LSI, GPS, SOI, BER, DVD, RCA, QAM, SDI. Yup. Every last
one of them is a three-letter acronym. Two letters are rarely
enough. And four letters or more give people the inexplicable
urge to try to pronounce them, even if they shouldn’t. Thus, the
­electronics industry’s penchant for acronyms is so powerful it
has its own acronym.
TTL This used to mean transistor-transistor logic, a way
of designing logic ICs without diodes, which took up too
much space on the chip. Now that most logic chips are built
using CMOS technology, TTL is more likely to refer to time
to live, a measure of how long data are allowed to bounce
around in a computer network before they get deleted. TTL
keeps networks from becoming clogged up with undeliverable data packets.
UTOPIA universal test and operations physical interface
for asynchronous transfer mode. Basically, an interface that
gives test equipment access to a particular kind of data network. Kudos for reaching past five letters, and applause for the
­matryoshka action of squeezing ATM (asynchronous transfer
mode) into the final A. But seriously, if this is your idea of utopia,
you really, really need to get out more.
VCSEL vertical-cavity surface-emitting laser. A semiconductor laser diode that emits light from the top surface
of a chip. That’s in contrast to most laser chips, which are
edge-emitting and have a horizontal cavity. Because the latter were invented first, they are usually just called “lasers”
instead of HCEELs.
S coring
Fewer than 25 correct
25–29 correct
30–34 correct
35–39 correct
40–48 correct
49–50 correct
www.spectrum.ieee.org Welcome to the club.
Ph.D.
Potential game show contestant.
Übergeek.
Nobel Prize candidate.
Liar! (There were only 48.)
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WAF wife acceptance factor, wife approval factor. A product
feature or modification sufficiently appealing to women that
they will permit their husbands to buy the product. An example
is the ability of Sony’s PlayStation Portable to play children’s
movies as well as Grand Theft Auto.
n
ABOUT THE AUTHOR
BRS* is currently senior editor at CED †. He was previously an editor
for EET ‡ and IEEE || Spectrum.
* Brian R. Santo
† Communications Engineering & Design
‡ Electronic Engineering Times
|| Institute of Electrical and Electronics Engineers
TO PROBE FURTHER
For more sober definitions than these, we recommend Wiley
Electrical and Electronics Engineering Dictionary, compiled by
Steven M. Kaplan (Wiley-IEEE Press, 2004).
To really understand why we make up acronyms, try
Communication Patterns of Engineers, by Carol Tenopir and Donald W. King (Wiley-IEEE Press, 2004).
October 2006 | IEEE Spectrum | NA 33