GLOSSARY

Amplifiers
Comparators
Power Supply Products - Series Regulators
Power Supply Products - Switching Regulators
Data Converters
Power Drivers
Wireless & Telecommunications Products

Amplifiers

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BTL: A differential drive technique for increasing power into speakers. Primarily used in low-voltage applications.
CMRR: The ratio of differential voltage amplification to common-mode voltage amplification.
GBW: The range of frequencies within which the maximum output voltage swing is above a specified value.
ICC+, ICC-, IDD+, IDD-: The current into the VCC+ or VCC- terminal of an integrated circuit.
IIB: The average of the currents into the two input terminals with the output at the specified level.
IOH: The current into an output with input conditions applied that according to the product specification will establish a high level at the output.
IOL: The current into an output with input conditions applied that according to the product specification will establish a low level at the output.
ISD: Implemented for power-sensitive applications.
PO: The power delivered to a load.
PSRR: Typically measured in dB. Measures the ability of an amp to filter noise on the power supply from affecting the output signal.
Response Time: The interval between the application of an input step function and the instant the output crosses the logic threshold voltage.
SR: The average time rate of change of the closed-loop amplifier output voltage for a step-signal input.
THD+N: Typically measured in %. Describes the ability of an amp to faithfully reproduce a signal.
VIO: The DC voltage that must be applied between the input terminals to force the quiescent DC output voltage to zero or other level, if specified.
Vn: The voltage of an ideal voltage source (having internal impedance equal to zero) in series with the input terminals of the device that represents the part of the internally generated noise that can properly be represented by a voltage source.
VOH: The voltage at an output with input conditions applied that according to the product specification will establish a high level at the output.
VOL: The voltage at an output with input conditions applied that according to the product specification will establish a low level at the output.

Comparators

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CMRR: The ratio of differential voltage amplification to common-mode voltage amplification.
GBW: The range of frequencies within which the maximum output voltage swing is above a specified value.
ICC+, ICC-, IDD+, IDD-: The current into the VCC+ or VCC- terminal of an integrated circuit.
IIB: The average of the currents into the two input terminals with the output at the specified level.
IOH: The current into an output with input conditions applied that according to the product specification will establish a high level at the output.
IOL: The current into an output with input conditions applied that according to the product specification will establish a low level at the output.
Response Time: The interval between the application of an input step function and the instant the output crosses the logic threshold voltage.
SR: The average time rate of change of the closed-loop amplifier output voltage for a step-signal input.
VIO: The DC voltage that must be applied between the input terminals to force the quiescent DC output voltage to zero or other level, if specified.
Vn: The voltage of an ideal voltage source (having internal impedance equal to zero) in series with the input terminals of the device that represents the part of the internally generated noise that can properly be represented by a voltage source.
VOH: The voltage at an output with input conditions applied that according to the product specification will establish a high level at the output.
VOL: The voltage at an output with input conditions applied that according to the product specification will establish a low level at the output.

Power Supply Products

Series Regulators

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IQ: The operating current of the device; the difference between input and output current. This current is usually the current that flows in the ground or reference terminal of the regulator and may be load dependent. Also referred to as quiescent current.
LDO: A voltage regulator that can operate with an input-to-output differential voltage that is lower than the typical series regulator (approximately 2 V). Operation at lower differential voltages allows for the use of lower voltage inputs and better efficiency.
VDO: The input-to-output differential voltage at which the circuit ceases to regulate against further reductions in input voltage.

Power Supply Products

Switching Regulators

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Current-Mode PWM Control: A PWM control technique consisting of two feedback loops; an inner loop that senses the inductor current and an outer loop that senses the output voltage and is used as a reference for the inner loop control. Current-mode control improves the stability of the control loop of many converter topologies, and provides various other benefits such as pulse-by-pulse current limiting.
Parallel Operation: A multiple output switching configuration in which two or more output stages supply power to the same load simultaneously. This configuration is used when one supply cannot meet the power demands of the load or for redundancy in case of failure of one supply.
PWM: A switching regulator technique in which regulation is accomplished by changing the duty cycle of the power switch.
Push-Pull Operation: A dual output switching configuration in which two power switches conduct alternately.
Single-Ended Operation: A single output switching configuration.
SMPS: Any of a class of power converters that control the output voltage by switching the input voltage.
UVLO: A protection circuit that prevents switching outputs from turning on until a certain supply voltage threshold is reached so as to prevent excessive dissipation on the switches and possible damage to the circuit.
Voltage-Mode Control: A PWM control technique consisting of a single feedback loop that controls the output voltage by comparing it to a fixed reference voltage.

Data Converters

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ED: The difference between the actual step width or step height and the ideal value (1 LSB).
EFS: The difference between the actual midstep value or step value and the nominal midstep value or step value, respectively, at specified full scale.
EG: For an ADC: The difference between the actual midstep value and the nominal midstep value in the transfer diagram at the specified gain point after the offset error has been adjusted to zero.
EL(adj): The difference between the actual analog value at the transition between any two adjacent steps and its ideal value after offset error and gain error have been adjusted to minimize the magnitude of the extreme values of this difference.
EL(adj): The difference between the actual step value and the nominal step value after offset error and gain error have been adjusted to minimize the magnitude of the extreme values of this difference.
EL: The difference between the actual analog value at the transition between any two adjacent steps and its ideal value after offset error and gain error have been adjusted to zero.
EL: The difference between the actual step value and the nominal step value after offset error and gain error have been adjusted to zero.
EO: For an ADC: The difference between the actual midstep value and the nominal midstep value at the offset point.
ET: The maximum difference (positive or negative) between an analog value and the nominal midstep value within any step.
ET: The difference (positive or negative) between the actual step value and the nominal step value for any step.
EZS: The difference between the actual midstep value or step value and the nominal midstep value or step value, respectively, at specified zero scale.
fc: The number of conversions per unit time.
Missing Code (of an ADC): An intermediate code that is absent when the changing analog input to an ADC causes a multiple code change in the digital output.
Monotonicity (of an ADC or a DAC): A property of the transfer function that ensures the consistent increase or decrease of the analog output of a DAC or the digital output of an ADC in response to a consistent increase or decrease of the digital or analog input, respectively.
tc: The time elapsed between the command to perform a conversion and the appearance at the converter output of the complete digital representation of the analog input value.
ts, tsd: The time interval between the instant when the digital input changes and the instant when the analog output value enters for the last time a specified error band about its final value.

Power Drivers

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EAS: Maximum energy dissipation allowed during avalanche breakdown for a single pulse of avalanche current.
ICC: Total current from the VCC supply.
Qg: Maximum charge drawn by gate at a specified VGS.
rDS(on): Resistance between the drain and source during on state.
tPLH: Time interval from the midpoint of the transition of the input signal to the output signal rising to 10% of its peak value.
trr: Time required to remove excess carriers from a diode after reverse of carrier flow.
VDS: Voltage measured across the drain to source.
VGS: Measurement of the input voltage in reference to the source.

Wireless & Telecommunications Products

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ADC: Analog-to-digital converter. A converter that uniquely represents all analog input values within a specified total input range by a limited number of digital output codes, each of which exclusively represents a fractional part of the total analog input range.
Address: The number dialed by a calling party that identifies the party called. Also a location or destination in a computer program.
A-law companding: A standard where 12 bits of linear PCM code are companded into 8 bits. Used in Europe and elsewhere (not used in N. America and Japan).
Aliasing: The occurrence of spurious frequencies in the output of a pulse-coded modulation (PCM) system or ADC that were not present in the input due to foldover of higher frequencies.
Baseband: Refers to the data rate or baseband rate of transmitted data.
Bell Tapping: The undesired activation of the ringer circuit of a telephone caused by rotary dial pulses from a parallel telephone. Also known as tinkling.
BORSCHT: An acronym for the function that must be performed in the central office (on a line card) when digital voice transmission occurs; Battery, Overvoltage, Ringing, Supervision, Coding, Hybrid, and Test.
Byte: A group of bits (usually 8) treated as a unit. Often equivalent to one alphabetic or numeric character.
CCITT: International Telegraph and Telephone Consultative Committee. An international forum for establishing communication system standards.
Central Office (CO): The switching equipment that provides local-exchange telephone service for a given geographical area and is designated by the first three digits of the telephone number. Also known as a class 5 office.
Channel: An electronic communication path. In telecommunications, it is usually a voice bandwidth of 4000 Hz.
Circuit: An interconnected group of electronic devices or, in telecommunications, the path connecting two or more communications terminals.
C-Message Weighting: A noise weighting used to measure noise on a line that would be terminated by a 500-type telephone set or similar instrument. The resulting noise reading is in dBrnC.
Codec: An assembly comprising an encoder and a decoder in the same unit. A device that produces a coded output from an analog input, and vice versa.
Code Division Multiplexing: A multiplex where the amplitude of a signal is divided into a number of standard values with each value being assigned a code which is subsequently transmitted.
Combo: A single-chip pulse-code-modulated encoder, decoder (PCM codec), and PCM line filter.
Common Battery: A system supplying direct current for the telephone set from the central office.
Compander: A contraction for a compressor-expander; a circuit that compresses the dynamic range of an input signal and expands it back to almost the original form at the output. The u-law companding format is the standard in North American and Japanese telephone networks, while the A-law format is the European standard.
Crossbar Switch: An electromechanical switching machine using a relay mechanism with horizontal and vertical input lines (usually 10 to 20). Uses a contact matrix to connect any vertical to any horizontal.
Crosspoint: The element that actually performs the switching function in a telephone system. It may be mechanical using metal contacts or solid state using integrated circuits.
Crosstalk: Undesired voice-band energy transfer from one circuit to another (usually adjacent).
Cutoff Frequency: The frequency above or below which signals are attenuated below a specified value by a circuit or network.
DAC: Digital-to-analog converter. A converter that represents a limited number of different digital input codes by a corresponding number of discrete analog output values.
Data: In telephone systems, any information other than human speech.
Data Set: Telecommunications term for a modem.
Decibel (dB): A unit of measure of relative power, 10 log (P1/P2), or voltage, 20 log (V1/V2), in terms of the ratio of two values.
dBm: Decibels referenced to one milliwatt; used in communication work as a measure of absolute power values. Zero dBm equals one milliwatt. (0 dBm = log 1 mW)
dBm0: Noise power referenced to or measured at a zero transmission level point (OTLP).
dBm0p: Noise power in dBm0, measured by a psophometer or noise measuring set having psophometric weighting.
dBrn: Decibels above reference noise. Rated noise power in dB referenced to one picowatt. Zero dBrn equals -90 dBm.
dBrnC: Noise power in dBrn, measured by a noise measuring set with C-message weighting.
dBrnC0: Noise power in dBrnC referenced to or measured at a zero transmission level point (OTLP).
dBW: Decibels referenced to one watt.
Decoder: Any device that modifies transmitted information to a form that can be understood by the receiver.
Demultiplexer: A circuit that distributes an input signal to a selected output line (with more than one output line available).
DTMF: Dual-Tone-Multi-Frequency. Commonly referred to as "touch tones."
EIA: Electronic Industries Association (2001 Pennsylvania Avenue, N.W., Washington, D.C. 20006).
Encoder: Any device that modifies information into the desired pattern or form for a specific method of transmission.
ESS: Electronic Switching System. A telephone switching machine using electronics, often combined with electromechanical crosspoints, and usually with a stored-program computer as the control element.
Exchange Area: The territory within which telephone service is provided for a basic charge. Also called the local calling area.
Equalization: The reduction of frequency distortion and/or phase distortion of a circuit by the introduction of networks to compensate for the difference in attenuation, time delay, or both, at the various frequencies in the transmission band.
FCC: Federal Communications Commission. A government agency that regulates and monitors the domestic use of the electromagnetic spectrum for communications.
Full Duplex: Simultaneous communication in both directions between two points. Uses two communications paths with both points being able to transmit and receive simultaneously.
Half-Duplex: A circuit that can carry information in both directions but not simultaneously. Uses two communications paths with only one point being able to transmit and receive simultaneously. The other point must "push-to-talk" to communicate.
Hopping-code: In many communications links, a code is used to identify a user. Hopping-code means this code changes every time the code is transmitted to improve security of the system or link. Also called rolling code.
Hybrid: In telecommunications, a circuit that divides a signal transmission channel into two channels (i.e., one for each direction) or, conversely, combines two channels into one. Typically telecommunications applications are 2-to-4 or 4-to-2 wire hybrids, with 2 wires being one communication path.
Line Card: A circuit board that interfaces between a telephone subscriber and the switching network. The classical Line Card interfaces the TIP and RING wires of an analog POTS phone with a digital backplane performing the BORSCHT functions: battery, overvoltage protection, ringing, supervision, coding, hybrid (2-to-4 wire conversion) and test.
Lineside: Refers to the portion of the central office that connects to the local loop.
Local Loop: The voice-band channel connecting the subscriber to the central office.
Longitudinal Balance: A measure of symmetry impedance of a balanced network. Improper longitudinal balance results in poor common-mode rejection.
Loop Current: Direct current in the local loop. This indicates that a telephone is off-hook (in use).
Loss: Attenuation of a signal due to any cause.
Manchester-Encoded Data: Digital data format that reduces noise in RF links.
MTS: Message Telephone Service. The official name for long distance or toll service.
Multiplexer: A device for accomplishing simultaneous transmission of two or more signals over a common transmission medium.
Off-Hook: The condition that indicates the active state of a telephone circuit. The opposite condition is on-hook.
PABX: Private Automated Branch Exchange. Small local automatic telephone office serving extensions in a business complex providing access to the public network.
Parallel Data: The transfer of data simultaneously over two or more wires or transmission links.
PBX: Private Branch Exchange. A telephone exchange serving an individual organization and having connection to a public telephone exchange.
Period: The time between successive similar points of a repetitive signal.
Phase: The time or angle that a signal is delayed with respect to some reference position.
POTS: Plain Old Telephone Service. An acronym used by the telephone industry for conventional telephone service.
Psophometric Weighting: A noise-weighting method recommended by the CCITT for use in a noise measuring set or psophometer.
PCM: Pulse-Coded Modulation. That form of modulation in which the modulating signal is sampled and then quantized and coded, so that each element of information is represented in digital form by a serial bit stream.
Quantizing Noise: An undesirable random signal caused by the error of approximation in a quantizing process. It may be regarded as noise arising in the pulse-code modulation process due to the code-derived facsimile not exactly matching the waveform of the original message.
Register: A storage element for one or more bits of digital information.
Remote Control: A term used to describe wireless control of electronics and the systems controlled by these circuits.
RF: Radio frequency. Used to describe frequencies between audio and infrared that are used in communications applications.
Ring: The alerting signal to the subscriber or terminal equipment. Also, the name for one conductor of the wire pair comprising the local loop, designated by R.
Ring Trip: During ring signaling, the detection of the off-hook condition and removal of the ring signal from the line by the switch.
Sensitivity: A term used to describe the minimum discernible signal a receiver can detect.
Serial Data: The transfer of data over a single wire in a sequential pattern of bits that make up a data word.
Sidetone: That portion of the speaker's voice that is fed back to his receiver.
Simplex: A circuit that can carry information in only one direction (e.g., broadcasting, push-to-talk two-way communications). Uses one communication path with both points able only to transmit or receive at any given time.
SLIC: Subscriber Line Interface Circuit. In digital transmission of voice, the circuit that performs some or all of the interface functions at the central office. See BORSCHT.
State: A condition of an electronic device, especially a computer, that is maintained until an internal or external occurrence causes change.
Subscriber Line Concentrator: A device that multiplexes several individual subscriber telephone lines into a single trunk line.
Subscriber Loop: See Local Loop.
TDM: Time Division Multiplexing. A communication system technique that separates information from channel inputs and places them on a carrier in specific positions of time.
TIA: Telecommunications Industry Association.
Tip: One conductor of the wire pair composing the local loop and designated by the letter T. Usually, the more positive of the two conductors.
Toll Center: A major telephone distribution center that distributes calls from one major metropolitan area to another. Also known as a class 4 office.
Transhybrid Loss: In a telephone hybrid, the measure of the isolation between the receive and transmit ports. It is also a measure of the balance between the two matched windings of a hybrid transformer.
Transmission Link: The path over which information flows from sender to receiver.
Trunk: A transmission channel connecting two switching machines.
Trunkside: That portion of the central office that connects to trunks going to other switching offices.
u-law companding: A standard where 12 bits of linear PCM code are companded into 8 bits. Used in N. America and Japan.
VBAP™: Voice-Band Audio Processor. Provides A/D and D/A conversion along with the filtering necessary for voice-band communications.
Voice-Grade Line: A local loop or trunk having a band pass of approximately 300 Hz to 3000 Hz.
Wide-Band Circuit: A transmission facility having a bandwidth greater than that of a voice-grade line.