Glossary Terms and Definitions Beginning with the Letter C

C 1. Capacitance, capacitor

2. Coulomb

3. Color portion of a video signal (see "Y/C" definition)

C/N Carrier-to-noise
C13 connector See IEC
C14 connector See IEC
CA Common anode
Cable See CATV
Cable Television See CATV
Cable TV See CATV
CAD Computer-aided design
CAN Controller Area Network. The CAN protocol is an international standard defined by ISO 11898.
capacitance See Capacitor
Capacitive Crosstalk A phenomenon where a signal on one line/trace is capacitively coupled to an adjacent line/trace.
Capacitive Voltage Regulator See Charge Pump
Capacitor A capacitor is a passive electronic component that consists of two conductive plates separated by an insulating dielectric. A voltage applied to the plates develops an electric field across the dielectric and causes the plates to accumulate a charge. When the voltage source is removed, the field and the charge remain until discharged, storing energy.

Capacitance (or C, measured in farads), dictates the amount of charge that can be stored at a given voltage (a one-farad capacitor charged to one volt will hold one Coulomb of charge).

Capacitor Charge Pumps See Charge Pump
CardBus 32-bit version of the PC card (formerly PCMCIA) standard
Carrier-free See UWB
CAS Column-Address-Strobe: The signal that tells the DRAM to accept the given address as a column-address; used with RAS and a row-address to select a bit within the DRAM
CAT 3 See CAT3
cat 5 See CAT5
CAT3 Category 3: Refers to Ethernet cabling that satisfies the criteria for the EIA/TIA-568 standard's Category 3, which allows data transfers up to 10Mbps.
CAT5 Category 5: Refers to Ethernet cabling that satisfies the criteria for the EIA/TIA-568 standard's Category 5, which allows data transfers up to 100Mbps.
Category 3 See CAT3
Category 5 See CAT5
CATV Originally "Community Antenna Television," a term which now refers to any community television system distributed by cable.
CBR Constant bit rate
CC/CV Charger Constant Current/Constant Voltage battery charger
CCCv Constant current/constant voltage
CCD Charge Coupled Device: One of the two main types of image sensors used in digital cameras. When a picture is taken, the CCD is struck by light coming through the camera's lens. Each of the thousands or millions of tiny pixels that make up the CCD convert this light into electrons. The accumulated charge at each pixel is measured, then converted to a digital value. This last step occurs outside the CCD, in an analog-to-digital converter (ADC).
CCFL Cold Cathode Fluorescent Lighting: Often used as a backlight for LCD displays.
CCFT Cold Cathode Fluorescent Tube: Often used as a backlight for LCD displays.
CCK Complementary code keying
CCM Continuous-conduction mode; crossconnect module
CDC Clock distribution circuit
CDD Clock Distribution Device or Clock Distribution Driver
CDF-AEC-Q100 See AEC-Q100
CDMA Code Division Multiple Access: A digital cellular technology that uses spread-spectrum techniques. Unlike GSM and other competing systems that use TDMA, CDMA does not assign a specific frequency to each user. Instead, every channel uses the full available spectrum. Individual conversations are encoded with a pseudo-random digital sequence.
CDR Clock/data recovery. Clock/data recovery is a function or circuit that extracts a clock signal from an incoming data stream.
CE Control Chip enable control
CE Gating See Chip-Enable Gating
Cell-Site See BTS
centimeter See cm
centimetre See cm
CH Chebyshev (filter)
Ch. to Ch. Skew (Ps Max) Channel-to-channel skew. A signal on one channel has a different phase than the same signal on another channel (delayed/skewed). This is measured in picoseconds, max.
Channel Associated Signaling Channel Associated Signaling (CAS): Some communications protocols include "signaling" functions along with data. Channel Associated Signaling protocols include signaling in the data channel (as opposed to a dedicated signaling channel).

Also called Robbed Bit Signaling.

Chans. Channels
Charge Coupled Device See CCD
Charge Injection A parameter pertinent to analog switches. As an analog switch turns on and off, a small amount of charge can be capacitively coupled (injected) from the digital control line to the analog signal path.
Charge Pump A power supply which uses capacitors to store and transfer energy to the output, often stepping the voltage up or down. Charge is transferred from one capacitor to another under control of regulator and switching circuitry.

Maxim offers both regulated and non-regulated charge pumps, as well as ICs with on-board charge pumps to boost internal voltages.

See application note 2031, "DC-DC Converter Tutorial" and application note 660, "Regulator topologies for battery-powered systems."
Charge Termination Method Method the battery charger uses to determine when to terminate the charging cycle.
CHATEAU CHAnnelized T1 and E1 And Universal HDLC controller
Chip 1. Integrated circuit: A semiconductor device that combines multiple transistors and other components and interconnects on a single piece of semiconductor material.

2. Encoding element, in Direct-Sequence Spread Spectrum systems.

Chip-Enable Gating A feature in microprocessor supervisory circuits which prevents the writing of erroneous data when power falls outside of spec. When the main power-supply voltage is below the minimum safe-operating limit, the feature disconnects the chip-enable signal path from the host microprocessor or microcontroller.
Chipping Rate See Mcps
chroma See Color Subcarrier
Chrominance The color portion portion of a composite video signal. Forms a complete picture once combined with the luminance component.
CID Consecutive identical digit(s)
CIM Cable integrity monitor
Circuit Board See Printed Circuit Board
CISC Complex instruction set computer (CISC): Computer hardware designed to support complex instructions, as opposed to RISC (reduced instruction set computer) architecture.
Class See Amplifier Class
Class A The simplest type of amplifier, class A amplifiers are those in which the output transistors conduct (i.e. do not fully turn off) irrespective of the output signal waveform. This type of amplifier is typically associated with high linearity but low efficiency.
Class AB Class AB amplifiers combine Class A and Class B to achieve an amplifier with more efficiency than Class A but with lower distortion than class B.

This is achieved by biasing both transistors so they conduct when the signal is close to zero (the point where class B amplifiers introduce non-linearities). The transistors transition to class B operation for large excursions.

So, for small signals both transistors are active, acting like a class A amplifier. For large signal excursions, only one transistor is active for each half of the waveform, acting like a class B amplifier.

Class B Class B amplifiers are those in which the output transistors only conduct during half (180 degrees) of the signal waveform. To amplify the entire signal two transistors are used, one conducting for positive output signals and the other conducting for negative outputs.

Class B amplifiers are much more efficient than class A amplifiers, but have high distortion due to the crossover point when the two transistors transition from on to off.

Class C A class C amplifier is a form of switching amplifier in which the transistors are on for less than a half cycle (less than 180 degrees) -- often, much less. For instance, the transistor may be on only during the top 10% of the signal excursion, delivering just a pulse.

Class C amps are very efficient because the transistors are off most of the time and when they are on, they are in full conduction. They deliver high distortion and are often used in RF circuits, where tuning circuits restore some of the original signal and reduce distortion. They are also used in low-fidelity applications where the distortion is not important, such as a siren speaker driver.

Class D Class D amplifiers are those that output a switching waveform, at a frequency far higher than the highest audio signal that needs to be reproduced. The low-pass filtered, average value of this waveform corresponds to the actual required audio waveform.

Class D amplifiers are highly efficient (often up to 90% or higher) since the output transistors are either fully turned on or off during operation. This completely eliminates the use of the linear region of the transistor which is responsible for the inefficiency of other amplifier types. Modern Class D amplifiers achieve fidelity comparable to class AB.

Class G Class G amplifiers are similar to class AB amplifiers except they use two or more supply voltages. When operating at low signal levels, the amplifier uses a lower supply voltage. As the signal level increases, the amplifier automatically picks the appropriate supply voltage.

Class G amplifiers are more efficient than class AB amplifiers since they use the maximum supply voltage only when required, while a class AB amplifier always uses the maximum supply voltage.

Class H Class H amplifiers modulate the supply voltage to the amplifier output devices so that it is never higher than necessary to support the signal swing. This reduces dissipation across the output devices connected to that supply and allows the amplifier to operate with an optimized class AB efficiency regardless of output power level.

Class H amplifiers are generally more complex than other designs, with extra control circuitry required to predict and control the supply voltage.

click See Click-and-Pop
Click-and-Pop Click-and-pop refers to the unwanted transient signals in the audio band that are reproduced by the headphone and/or speaker when the audio device driving it is either:
  • powered up (power applied)
  • powered down (power removed)
  • brought out of shutdown (power applied previously)
  • forced into shutdown (power still applied)
Click/Pop Reduction A feature that eliminates "clicks" and "pops" — unwanted transient noise signals during power-up, shutdown, connection, etc.
Clock and Data Recovery The process of extracting and reconstructing clock and data information from a single-wire/channel, serial data stream.
Clock Distribution Device See CDD
Clock Distribution Driver See CDD
Clock Jitter A periodic waveform (especially a clock) is expected to cross certain thresholds at precisely timed moments. Variations from this ideal are called jitter.

For more information and illustrations, see:

Clock Recovery See Clock and Data Recovery
Clock Recovery Data See Clock and Data Recovery
Clock Reduction See Clock Throttling
Clock Throttling Reducing the frequency or duty-cycling the clock of an integrated circuit usually for the purpose of reducing heat generation.
cm Centimeter: 1/100 of a meter, 0.39 inches.
CMF Current-mode feedback
CMI Code matrix insertion
CML Current-mode logic
CMOS Complementary metal-oxide semiconductor technology in which p- and n-channel MOS transistors are used in tandem.
CMRR Common Mode Rejection Ratio: The ability of a differential amplifier to not pass (reject) the portion of the signal common to both the + and - inputs.

See the tutorial, Understanding Common-Mode Signals.

CMVR See Input CMVR (V)
CNC Computer numeric control
CO Coarse offset
Code Division Multiple Access See CDMA
CODEC Short for compressor/decompressor, a codec is any technology for compressing and decompressing data. Codecs can be implemented in software, hardware, or a combination of both.
COG Chip-on-glass
Coherent Sampling Describes the sampling of a periodic signal, where an integer number of its cycles fits into a predefined sampling window.
COLC Correction loop capacitor
Cold Cathode Fluorescent Lighting See CCFL
Cold Cathode Fluorescent Tube See CCFT
color signal See Chrominance
Color Subcarrier A modulated carrier, added to a television signal, to carry the color components.

Examples: In NTSC television, a 3.579545MHz color subcarrier is quadrature-modulated by two color-difference signals and added to the luminance signal. The PAL television standard uses a subcarrier frequency of 4.43362MHz.

See: Video Basics

Column-Address-Strobe See CAS
Common Mode Rejection Ratio See CMRR
Common-Mode See Common-Mode Signals
Common-Mode Signals Common-mode signals are identical signal components on both the + and - inputs of a differential amplifier or instrumentation amplifier. A common example is in a balanced pair, where a noise voltage is induced in both conductors. Another example is where a DC component is added (e.g. due to a difference in ground between the signal source and the receiver).

In an ideal differential amp, the common-mode element is cancelled out, since the differential (+ and -) inputs should subtract out the identical components. A measurement of the actual ability to do this is called the Common Mode Rejection Ratio, or CMRR.

See the tutorial, Understanding Common-Mode Signals.

comp See Comparator
Comp. Prop. Delay Comparator propagation delay. This is the lag between the input crossing the comparator threshold, and the output changing states.
compander Signal processing technique which uses both compression and expansion to improve dynamic range and signal-to-noise ratio.

A signal is passed through a non-linear transformation prior to transmission. A reverse of this transformation occurs at reception. The transformation is such that quiet portions are boosted and loud portions reduced. Noise is reduced because the quiet signals are louder, compared to the noise in the transmission channel.

Used in digital, PCM, transmissions as well as analog applications. Dolby is a common example of a compander-based noise reduction system.

companding See compander
Comparator A comparator is a device that accepts two analog inputs, compares the inputs, and produces a binary output that is a function of which input is higher. If the non-inverting (+) input is greater than the inverting (-) input, then the output goes high. If the inverting (-) input is greater than the non-inverting (+) input, then the output goes low.

When described that way, the comparator resembles a 1-bit ADC.

A simple comparator can be achieved using an op amp without negative feedback. Its high voltage gain enables it to resolve very small differences in input voltage. But op amps used this way are generally slower than comparators and lack special features, such as hysteresis and internal references.

Application Note 886: Selecting the Right Comparator goes into more details on how comparators work, their specifications, common comparator features, and how to select a comparator that best fits your needs.

complementary See Push-Pull
Complete Central Office Line Interface Central Office Line: telephone line
Complex instruction set computer See CISC
CompoNet CompoNet is a four-wire, industrial, bus with a master-slave architecture. It is used at the lower network levels to transmit bit or word information, such as for use in sensors and actuators. Up to 256 slaves are supported on a bus. Data rates of 93.75kbps to 4Mbps and network lengths up to 1500 meters with repeaters are possible. CIP is used as the underlying protocol.
Constant Current Constant Voltage See CC/CV Charger
Contact Bounce When a mechanical switch or relay closes, the switch elements will often bounce, even if only briefly, before making final contact. This is of consequence if downstream elements are sensitive to the switching transients. A contact debouncing circuit is often used to remove the transients.
Contact Discharge An ESD test method where the ESD generator makes direct contact with the device under test (DUT).
Controller See DC-DC Controller
Controller Area Network See CAN
Coplanar Line A line which is in the same plane as another line. Any two intersecting lines must lie in the same plane, and therefore be coplanar.
Coulomb Coulomb (abbreviated C) is the standard measure of electrical charge.

Named after Charles-Augustin de Coulomb, it is the amount of charge accumulated on a one-farad capacitor charged to one volt; or the amount of charge transported by a one ampere current in one second.

Coulomb Counter See Battery Fuel Gauge
Coulomb Counting See Battery Fuel Gauge
CP Comparable part
CPGA Ceramic pin grid array, an IC packaging technology.
cps See Hz
CPU Throttling See Clock Throttling
CR See Lithium batteries
CRC Cyclic Redundancy Check: A check value calculated from the data, to catch most transmission errors. A decoder calculates the CRC for the received data and compares it to the CRC that the encoder calculated, which is appended to the data. A mismatch indicates that the data was corrupted in transit. Depending on the algorithm and number of CRC bits, come CRCs contain enough redundant information that they can be used to correct the data.
CRIL Command register and interface logic
Cross Talk See Capacitive Crosstalk
Crossover In an output stage (or similar amplifying stage which uses one device to pull the signal up and another to pull the signal down), the region in which the high-side device is turning on and the low-side device is turning off, or vice versa.
Crosstalk See Capacitive Crosstalk
Crowbar Circuit A crowbar circuit is a power supply protection circuit that rapidly short-circuits ("crowbars") the supply line if the voltage and/or current exceeds defined limits. In practice, the resulting short blows a fuse or triggers other protection, effectively shutting down the supply.

It is usually achieved by an SCR or other silicon device, or by a mechanical shorting device.

Probably named for the concept of using a big metal bar to mechanically provide the short circuit, as might be used done in a high-current application; or from the appearance of a crowbar circuit's I-V curve.

See: Protection and Isolation products.

CRT A cathode ray tube (CRT) is a display device which uses an electron beam to energize a phosphorescent coating. The beam is generated at one end of an evacuated glass tube and controlled by electrostatic and/or electromagnetic fields to strike the coating at the other end, where light emitted when electrons strike the phosphor constitute the display.
Cryptanalysis The art and science of breaking encryption or any form of cryptography.
CS Chip select
CSA See Current-Sense Amplifier
CSP Chip Scale Package: An IC packaging technology in which solder balls take the place of pins, making the smallest package available. When heated, the solder balls alloy to matching pads on the circuit board.
CTIM Retry timeout capacitor
CTON Startup timer capacitor
current See Ampere
current controlled voltage source See Transimpedance Amplifier
Current Mode Feedback An alternative op amp topology usually used in high-speed amplifiers. It is sensitive to feedback impedance, and cannot be used as an integrator.
Current Mode PWM See Current-Mode Controller
Current Sensing See Current-Sense Amplifier
Current Sensor See Current-Sense Amplifier
Current-Mode Controller A DC-DC switching regulator which regulates its output voltage by varying the peak inductor current on a cycle-by-cycle basis to output a regulated voltage despite variations in load-current and input-voltage.
Current-Sense Amplifier An amplifier that measures current by measuring the voltage drop across a resistor placed in the current path. The current sense amp outputs either a voltage or a current that is proportional to the current through the measured path.
cycles See Hz
Cyclic Redundancy Check See CRC