Semiconductor Test Glossary

Test Glossary

ac signal - a signal that has alternating polarity, typically a sinusoidal wave of constant frequency

active filter - an electronic filter that combines active devices such as operational amplifiers with passive components like resistors and capacitors; active filters are typically better than purely passive filters

active load - a programmable circuit that can serve as a pullup or pulldown load for a DUT (device under test) pin

active test site - an operational test site that has its tester channel numbers included in the test program's pin lists

ADC - see "Analog-to-Digital Converter"

ADM - acronym for "Add/Drop Multiplexer" : a device that adds (inserts) or drops (removes) lower-data-rate channel traffic from a higher-rate aggregated channel

ADPCM - acronym for "Adaptive Differential Pulse Code Modulation": a compression technique that encodes only the difference between sequential samples

ADSL - acronym for "Asymmetric Digital Subscriber Line" : a method of moving data over regular phone lines faster than a modem

AFE - acronym for "Analog Front End" : the analog portion of a circuit which precedes analog-to-digital conversion

AGC - acronym for "Automatic Gain Control": a circuit that modulates an amplifier's gain in response to the relative strength of the input signal in order to maintain the output power

algorithm - a set of rules with a finite number of steps for solving a problem or performing a task, such as testing

aliasing - the phenomenon wherein a signal is falsely represented as a lower-frequency signal by digital data obtained from digitization of the signal using an insufficient sampling frequency

alias frequency - a false lower-frequency component that emerges when an analog signal is digitized at an insufficient sampling rate

ambient level - the intensity of noise and signals that are present at a test location when the device under test is not active.

amplitude modulation (AM) - a modulation method in which the carrier amplitude changes with the input signal amplitude

analog signal - a variable and non-discrete electrical signal that can be transformed to represent something in the physical world for processing, transmission, amplification

analog-to-digital conversion - the process of representing an analog signal with digital data

analog-to-digital converter (ADC or A/D converter) - a semiconductor device or electronic circuit that converts an analog signal input into a digital code output

anechoic chamber - an enclosure especially designed with walls that absorb sound or radiation, creating an essentially free-field environment for testing.

anti-alias filter - a low-pass filter that removes or attenuates noise and aliased high-frequency components of an analog signal prior to its conversion into a digital value

APM - acronym for "Advanced Power Management": power management standard for computers that provides five power states: Ready, Stand-by, Suspended, Hibernation, Off

aspect ratio - the ratio of a video picture's width to its height

assembler - a program that translates mnemonic codes into binary data that can be executed by a computer

asynchronous - an action that takes place at an arbitrary point in time, without being synchronized with a reference timer or event

asynchronous transfer mode (ATM) - a fast-packet switching technology that uses asynchronous time-division multiplexing

ATE - acronym for "Automatic Test Equipment", which is an automated and usually computer-controlled machine for testing semiconductors, electronic circuits, and printed circuit board assemblies

attenuation - the reduction of a signal's intensity or power from the time of its transmission to the time of its receipt

autorange - the automatic adjustment of the measurement range of a measuring instrument to maximize the accuracy of the measurement taken of a quantity at its input

averaging - mathematical smoothing of the results of several measurements by summing them up and dividing the sum by the number of samples

AWB - arbitrary waveform generator: an instrument that can be programmed to provide signals with special waveform characteristics

band-pass filter - a filter that passes only those signals with frequencies falling between two predefined frequencies

bandwidth (BW) - a range of frequencies over which a system works without degrading the original signal

baseband - the signal that is unmodulated in video and audio transmissions

BCD - acronym for "binary-coded decimal" : representation of a number in which each decimal digit (0-9) is encoded in binary, with four bits per decimal digit

BER - acronym for "bit error rate" : a measure of the number of erroneous bits which can be expected in a specified number of bits in a serial stream

bidirectional - the ability to accommodate signals traveling in either direction though a single channel

bipolar - 1. a signal that includes positive and negative values; 2. a type of semiconductor device whose operation depends on the movement of two types of carriers, i.e., electrons and holes; 3. a device that can operate with both positive and negative voltages

bipolar mode - the mode of operation of a converter wherein both positive and negative analog values are used

bipolar offset - the deviation of the actual value of a converter's major carry transition from '011111111111' to '100000000000' from its ideal value, i.e., an analog input value that is 1/2 LSB below the analog common.

BIST - acronym for "Built-in Self Test": the technological approach of building tiny tester models onto the integrated circuit so that it can test itself

bit error ratio - the number of erroneous bits divided by the total number of bits transmitted, received, or processed over a specified duration

bit map - a set of data that define the colors or gray levels in an image

blob - a continuous region in an image in which all pixels have the same gray level

blooming - saturation of light-sensing elements in a TV camera, leading to clipping when the camera is at the maximum brightness level

Bluetooth - a technology that allows voice and data connections between a wide range of mobile and stationary devices through short-range digital two-way radio

boundary scan - a generic term for IEEE 1149.1, which is a methodology allowing complete controllability and observability of the boundary (I/O) pins via a standard interface

broadband - a transmission medium with enough bandwidth to carry multiple voice, video, or data channels simultaneously

buck - to produce an output voltage that is lower than the input voltage

boost - to produce an output voltage that is higher than the input voltage

burst mode - a temporary very high-speed data-transfer mode

channel - a single testing path dedicated by an automatic test equipment to one device-under-test (DUT) pin

channel-to-channel skew - a phenomenon wherein the signal on one channel has a different phase than the same signal on another channel

characterization test - a test or series of tests designed to determine the operating regions and reliability of a device under varied operating conditions

checksum - the sum of a group of data values usually transmitted with the data to assist in error detection

chrominance - the color information of a video signal that defines the hue and saturation, but not the brightness or luminance, of the signal

clamp voltage - the maximum limit for voltage excursions exhibited at a node, usually set by a clamping circuit

CMRR - see "common-mode rejection ratio"

codec - an abbreviation of coder-decoder; a device that can encode and as well as decode information

cold-junction compensation - an artificial reference level that compensates for ambient temperature variations in thermocouple circuits

color bars - standard test pattern on a display screen of fully saturated colors (red, green, blue, magenta, cyan, and yellow) plus black and white

common-mode rejection ratio (CMRR) - a measure of a device or instrument's ability to ignore or reject a signal that is common to its inputs, relative to ground

comparator - a circuit or device whose output is a digital logic state that depends on whether its input signal is above or below a given threshold level during a specified time interval

compiler - a program that translates high-level-language statements into machine language codes that a computer can execute

compliance voltage - the voltage range that a current source or sink can produce within its constant current specifications

composite sync - a video signal that contains horizontal-sync pulses, vertical-sync pulses, and equalizing pulses only, with a no-signal reference level

composite video - a video signal composed of luminance (black and white) information, chrominance (color) information, blanking pulses, sync pulses, and a color-burst signal

concurrent testing - the process of performing different tests simultaneously on one or more devices that may be different from each other; see also 'parallel testing'

cone of logic - the combinational logic in a circuit that resolves to a single observe point

conducted emission - electromagnetic energy that is propagated along a conductor

conducted interference - conducted emission that is undesired

conversion time - the time required by an ADC or DAC to provide its final output

convolution - the integration of the product of two functions in time; convolution in the time domain is equivalent to multiplication in the frequency domain

coprocessor - a processor that operates with the CPU to boost speed

counter - 1. in hardware, a circuit that counts pulses; 2. in software, a memory location used to store a count of event occurrences

counterpoise - the reference-plane portion (grounded or ungrounded) of an unbalanced antenna

CRC - see "Cyclic Redundancy Check"

cross assembler - a program that runs on one computer and generates instructions for another type of computer

cross coupling - the coupling of a signal from one channel, circuit, or conductor to another, where it becomes an undesired signal

cross modulation - modulation of a desired signal by an undesired signal

crossover - the operating region of an output stage (that uses a high-side device to pull up the signal and a low-side device to pull down the signal) wherein the high-side device is turning on and the low-side device is turning off, or vice versa

crosstalk - a phenomenon wherein one or more signals interfere with another signal

crowbar current - short-circuit current from the positive or the negative supply that occurs when both the P- and N-channel drivers of a complimentary output driver are "on" simultaneously

current loop - a communications method that transmits data as current flow over relatively long distances and through environments with relatively high noise

current-sense amplifier - a device that measures a current through a low-value sense resistor and outputs a proportional voltage or current

CUT - acronym for "Circuit Under Test": the target device or circuit undergoing electrical test; almost synonymous with DUT

cycle time - the duration from the start of one cycle to the start of the next

cyclic redundancy check (CRC) - a mathematically generated number that data receivers use to verify the proper bit arrangement in a bit stream

cyclization - the process by which discrete time signals (such as supplied in VCD) are mapped to a representation amenable to automatic test equipment

DAC - see "Digital-to-Analog Converter"

data acquisition (DAQ) - the process of gathering information from sources such as sensors and transducers

data collection - the process of collecting selected information in a file during a specified operation

data logging - the recording of selected information during a specified operation, such as actual test parameter measurements and data for each device tested during automatic electrical testing

data reduction - the transformation of raw data, such as those logged during a device-test run, to human-usable forms, such as graphical representations and tables

DBT - acronym for "Defect-Based Test": a test development philosophy that considers fab defect densities and device circuit layout in the development of tests which are focused primarily on uncovering defects that will most impact the yield

debounce - to remove any ripple signals created by a mechanical switch, key, or pushbutton, thereby resulting in a cleaner output from the switch

decibel (dB) - a logarithmic measure of the ratio of two signal levels, i.e., dB = 10 log (Power1 / Power2) or dB = 20 log (Voltage1 / Voltage2)

decoupling-network - an electrical circuit that prevents signals used on a device or system from affecting other devices or systems

defect - a physical or chemical imperfection; a characteristic that does not meet required specifications

defective - a manufactured product that has one or more defects

defect level - the proportion of electrical rejects inadvertently shipped to customers due to the inherent imperfection of any testing or inspection process; see also "dpm"

degradation - an unwanted change in the performance of a device or system

design rules - a set of rules (usually dimensional and lay-out rules) that governs how an integrated circuit must be fabricated (wafer fab design rules) or assembled (assembly design rules)

detectability - the degree to which it is possible to observe a faulty output behavior of a failing component

DFT - acronym for "Design For Test": the practice of adding hardware hooks or features to integrated circuits in order to facilitate effective and inexpensive testing

diagnostic tests - tests performed to check if a system (such as a test system) is malfunctioning and if so, to determine the possible cause(s) of the malfunction and the corresponding repair strategy

differential non-linearity - the maximum deviation between two adjacent steps (a transition of 1 LSB) that is exhibited by a DAC or ADC

digital-to-analog conversion - the process of changing digital data or discrete values into an analog voltage or current

digital-to-analog converter (DAC or D/A converter) - a semiconductor device or electronic circuit that converts digital information into a corresponding analog voltage or current

dipole - an antenna made of a straight conductor (usually not longer than half a wavelength) that is divided at its electrical center and connected to a transmission line.

direct memory access (DMA) - the direct transfer of information between a computer's memory and a device while the computer's CPU does something else.

dithering - a technique for improving digitization when quantization noise or error can no longer be treated as random

dpm - 1. acronym for 'defective parts per million' or the defect level expressed as the number of defective parts per million units produced; 2. acronym for 'defects per million' or the defect level expressed as the number of defects observed per million units produced

driver - 1. a circuit that amplifies and conditions input signals for application to a DUT pin 2. software that controls a specific piece of hardware or device

DUT - acronym for "Device Under Test": the target device undergoing electrical test

DUT fixture or DUT board - a circuit board that interfaces the test head of the tester to a device-under-test (DUT) socket, a probe card, or a connector for the device handler

dynamic range - the ratio of the full-scale range (FSR) of a data converter to the smallest step that the converter can resolve

EDA - acronym for "Electronic Design Automation": a system consisting of design tools and environment utilized to render the logic, schematics, insert scan, insert BIST, etc. for a new chip design

edge - an abrupt voltage or current change, i.e., the step transition point of a pulse

edge detection - a technique that locates an edge by examining an image for abrupt changes in pixel values

edge-placement accuracy - a measure of how close an edge can be positioned on a desired point with respect to a reference

electromagnetic compatibility (EMC) - the ability of an electronic equipment to operate in its intended operating environment without any degradation caused by ambient electromagnetic interference, and without interfering with other equipment in the same environment

error - a discrepancy between the actual or real value and the measured value

event counter - a circuit that counts the occurrences of a certain condition

failure -the inability of a product to meet any of its specifications, whether electrical or visual-mechanical

false accept - a unit that is electrically bad but nonetheless accepted by the test equipment for one reason or another, e.g., incorrect test guardbands, poor test designs, insufficient test coverage, equipment problems, etc.

false color - color added to an image to call attention to details that aren't readily perceptible or to create special effects

false reject - a unit that is electrically good but nonetheless rejected by the test equipment for one reason or another, e.g., contact issues, incorrect test guardbands, equipment problems, etc.

far field - the region in which the power flux density from an antenna obeys the inverse-square law, e.g., for a dipole antenna, distances beyond L/2 are far-field regions

fault - a software model of a defect, or class of defects

fault coverage - the ability of a test or set of tests to actually detect faults or failures that are theoretically detectable based on a particular fault model

fault dominance - the phenomenon wherein a fault causes a device to exhibit a more serious deviation from device specifications, in comparison to another fault (or other faults) on the same device

fault equivalence - the phenomenon wherein two different faults affect the same device in the same way and to the same extent

field of view - the area of the object under view as represented at the focal plane of a camera

field strength - the measurement of either the electric field or the magnetic field that is made in the far field

file transfer protocol (FTP) - a protocol that transfers files over the Internet

filter - a mathematical operation or an actual circuit or device that selectively removes noise from a signal; see also low-pass, band-pass, and high-pass filters

firewall - hardware or software that protects a network from unauthorized access

firmware - a program permanently recorded in ROM

flaw detection - an image analysis technique that checks an object for unwanted features of unknown shapes at unknown positions

flash converter - a converter that performs its conversion directly, making it the fastest converter

force - to apply a specific stimulus to a DUT pin; see also "sense" and "force/sense"

force/sense - a measurement technique wherein a voltage (or current) is forced at a point in the circuit and the resulting current (or voltage) is measured at the same point

format - to produce a waveform from pattern data and timing information in accordance with a given format mode

frame grabber - a device that digitizes an image and stores it in a computer's memory

frame relay - a technology for transmitting data packets in high-speed bursts across a digital network

FSK - acronym for "Frequency Shift Keying": a method of transmitting digital data by shifting the frequency of a carrier signal to represent binary 1's and 0's

functional test - 1. the process of testing a device for its ability to perform its intended function (examples: output swing tests for op amps, conversion tests for ADC's/DAC's, read/write tests for memories); 2. a process that applies pattern vectors to a device and checks the output to determine if the device is operating according to its truth table; see also: "parametric test"

genlock - extraction of horizontal-sync and vertical-sync signals from a video signal and the use of those signals in synchronizing video equipment

glitch - an undesirable momentary pulse that can accidentally trigger events or errors

go/no-go test - a test that simply indicates whether the DUT passes or fails

gray level - the brightness value assigned to a pixel; values range from black, through gray, to white

gray scale - the set of discrete gray levels defined for an imaging system or imaging software, e.g., in an eight-bit system, the gray scale runs from 0 to255

ground - 1. a common reference point for an electrical system; 2. an electrically neutral, non-current-carrying wire that has the same potential as the surrounding earth used for electrical safety purposes

ground plane - a conducting surface or plate used as a common electrical reference point for circuits

guard band - an adjustment made to a DUT’s test program limit to take into account tester accuracy, tester repeatability, tester reproducibility, and tester-to-tester correlation in testing the DUT against the corresponding published datasheet limit

half-duplex - data transmission over a circuit that's capable of transmitting in either direction, but not simultaneously

harmonic distortion (HD) - a form of distortion in analog circuits involving harmonics, i.e., signals whose frequencies are integer multiples of the input signal; calculated as the ratio of a single harmonic to the level of the original signal; see also "total harmonic distortion"

hexadecimal - the base-16 numbering system: 0,1,2,3,4,5,6,7,8,9,10,A,B,C,D,E,F

high-pass filter - 1. a circuit that attenuates low-frequency components in an analog signal; 2. a mathematical operation that emphasizes details in an image

high side component - a component connected between the positive power supply and the load; see also "low side component"

hipot - high-potential

histogram - a frequency plot of data from a normal distribution

horizontal blanking - the blanking signal that occurs at the end of each video scanning line

horizontal sync - the portion of a video signal that indicates the end of a line of video information

hue - the distinction between colors, such as red, blue, green, and yellow; white, black, and gray are not considered to be intensities, not hues.

intermodulation distortion (IMD) - a phenomenon in which non-linear circuits or devices create unwanted frequency components that are not in the original RF signal

I/O address - a specific hardware circuit or software value that the CPU uses to distinguish between the different boards in a system

I/O channel - an input/output tester port that is capable of both stimulating a device pin and monitoring a response from the same pin

image analysis - a technique that extracts features and descriptions from images

image processing - improvement of a source image, or transformation of a source image into one that provides more information about specific properties of the source image

immunity - the ability of a piece of equipment to reject or not be affected by an electrical disturbance

impulse - an electromagnetic pulse of very short duration, i.e, shorter than one cycle at the highest frequency being considered

inhibit - to turn off a driver, placing it in a state that approximates an open circuit

input bias current - the amount of current flowing in or out of each of a non-ideal operational amplifier's inputs

input isolation - any mechanism for isolating a circuit or device's inputs from other circuits

input offset current - the mismatch or difference between the input bias currents flowing through the inputs of an operational amplifier

input offset voltage - the slight voltage present across a non-ideal operational amplifier's inputs brought about by its non-zero input offset current

instrumentation amplifier - a closed-loop amplifier with high-impedance differential inputs and an output that is single-ended with respect to the reference terminal

integral non-linearity - the maximum deviation exhibited by a DAC or ADC from the ideal straight line connecting its zero and full-scale analog value

interpreter - a program that translates a high-level-language program one instruction at a time into computer code, effecting the execution of the instruction as soon as it is translated

interrupt - a input signal that requires and gets immediate attention from a computer's CPU

interrupt handler - the software routine that handles an interrupt's request for service

interrupt vector - a type of interrupt that immediately points a computer to a new series of instructions

invalid reject - see "false reject"

isolation amplifier - an amplifier that provides electrically isolated inputs and outputs that let it amplify a differential signal that is superimposed on a high common-mode voltage

isolation voltage - the voltage that an isolated circuit can normally withstand; usually specified from input to input or from any input to the amplifier output

isotropic - having properties that have equal value in all directions

JTAG - acronym for "Joint Test Action Group": now essentially synonymous with the IEEE 1149.1 standard for Test Access Port and Boundary Scan

jitter - a slight deviation of a transmission signal in time or phase that can introduce errors and loss of synchronization

laser - acronym for "light amplification by stimulated emission of radiation"; a highly collimated and coherent beam of light

LBIST - acronym for "Logic Built In Self Test": a form of BIST targeted at testing random logic

leakage inductance - an inductive component present in a transformer that results from imperfect magnetic linking of one winding to another

least significant bit (LSB) - the smallest step that a converter can recognize

level translator - a device that translates a logic signal level from one type to another, e.g., ECL to TTL.

library - a collection of routines, data, or other materials in a file from which a user can draw for use in a project such as a test program

line - in imaging, the coordinate that defines the vertical location of a pixel in an image

linear - having an output that is directly proportional to the input, e.g., Vout=constant*Vin

linearity - a measure of how close a device's linear response is to a straight line

line regulation - the ability of a voltage regulator to maintain its output voltage despite variations in its input voltage

lot - a group of similarly-processed semiconductor devices, usually from the same production run, treated as a homogeneous population

low drop out (LDO) - a characteristic of a linear voltage regulator that allows it to operate even when the input voltage barely exceeds the desired output voltage.

low-pass filter - 1. a circuit that attenuates the high-frequency components of an analog signal; 2. an operation that blurs details in an image

low side component - a component connected between the load and ground; see also "high side component"

luminance - the brightness or intensity of a color

macro - a set of program steps combined by a user or a programmer that act as a single and more powerful program step

MBIST - acronym for "Memory Built In Self Test": a BIST approach that is specific to memory testing

mismatch - a non-ideal coupling of two circuits, usually resulting in partial signal reflection of a signal that passes from one circuit to the other, subsequently leading to measurement error

monochrome - an image represented by a single color

monopole - an antenna that consists of a straight conductor usually measuring not more than one quarter of a wavelength long, mounted immediately above and at a right angle to a ground plane.

monotonicity - a characteristic of a DAC in which the analog output increases as the digital code input to it increases

most significant bit (MSB) - the biggest step (corresponding to just a single bit) that a converter can recognize

multidie probing - the parallel testing of more than one die (on a wafer) at a time using several probes

multiplexing - 1. the process of combining of two or more signals into one in such a way that they can later be separated again; 2. the process of using a single common output for several inputs, with only one of the inputs connected to the output at a time

multiplexer (MUX) - a semiconductor device, circuit, or set of electromechanical switches arranged to select one of many inputs for connection to a single common output

multisite - refers to a single test head with more than one test site

multisite testing - the use of a single test program and a single 'multi-site' test head to test two or more devices in two or more test sites, either in parallel or in sequence

noise - undesirable electrical interference to a signal

noise distortion - the nonlinear behavior that circuits or devices exhibit when driven with a broadband noise signal

noise floor - 1. the noise level below which no information can be obtained from a signal; 2. the minimum discernible signal that can be detected by a receiver

non-observable fault - a fault whose effects cannot be measured at any network output

NTSC - acronym for "National Television System Committee": a 60-Hz standard for encoding color video signals used in North America, Canada, Japan, and most of South America.

Nyquist frequency - a sampling frequency that is twice the highest frequency component of the signal to be sampled

Nyquist Sampling Theorem - a theorem that states that a signal must be sampled at a rate that's twice the signal's highest frequency to prevent any loss of information about the signal

offset voltage - see input offset voltage

open area - an open and flat test site used for measuring electromagnetic interference, requiring sufficiently low ambient radiation to permit testing

open loop gain - the ratio of an operational amplifier's output voltage to its differential input voltage without any external feedback

operational amplifier - an open-loop high gain amplifier with high-impedance differential inputs and a single output; an op amp can be configured to function in many different applications

operational test site - a test site on a multi-site test head declared in the test program to be functional and available for use

optical isolator - a device that links two circuits through an optoelectronic transmitter and receiver, such that there is no direct electrical connection between the two circuits

output isolation - any mechanism for isolating a circuit or device's output from other circuits

PAL - acronym for "phase alternation line": a 50-Hz composite color video standard used in Western Europe, India, China, and some Middle Eastern countries; see also NTSC, SECAM, RS-170

palette - the range of colors that a display can produce

parallel testing - the process of performing identical tests simultaneously on more than one device of the same type; see also 'concurrent testing'.

parametric test - the process of testing a device against a specification for a measured electrical characteristic or quantity, such as voltage or current

passive filter - a filter that utilizes only passive components such as resistors, capacitors, and inductors

pattern - the binary data applied to and expected from a DUT during a functional test

pin list - an array of pin-name/channel-number pairs

pitch - the center-to-center distance between adjacent leads on a semiconductor package

pixel - abbreviation for "picture element": 1. The fundamental picture element in a digital image; 2. the coordinate unit used to define the horizontal location of a pixel in an image

pogo pin - a kind of spring-loaded pin used to contact pads on a circuit board; it consists of two small tubular sections (the smaller one of which has the contactor at its end) joined together by an internal spring

polarization - the orientation of the field vector in a radiated field

polling - a round-robin canvassing of the computer inputs to determine which ones are active or have fresh data, often synchronized in software to a clock or external trigger

power supply rejection ratio (PSRR) - the ability of a device to prevent its output from being affected by power supply noise, ripples, spikes, and excursions

PSRR - see "power supply rejection ratio"

quadrature - the relation between two waves of the same frequency, but one-quarter of a cycle (90°) out of phase

quantization - the process whereby a continuous signal is divided into non-overlapping subranges, each of which is assigned its own discrete (digital) value

quantization error - the inherent uncertainty in digitizing an analog value that is caused by the finite resolution of the conversion process; increasing the resolution of an ADC reduces the uncertainty

radio-frequency interference (RFI) - high-frequency interference with radio reception

rail-to-rail - the span from the negative power supply to the positive power supply

range - 1. the difference between the minimum and maximum values of a parameter, such as voltage; 2. a statement of the minimum and maximum values of a parameter

repeatability - the ability of an instrument to give the same output or reading when repeatedly operated under identical conditions by the same user

reproducibility - the ability of an instrument to give the same output or reading when operated under identical conditions by different users

resolution - 1. the smallest division to which a measurement can be determined; 2. the number of bits that an ADC or DAC has

R2R ladder - a resistor network that provides basic binary-current division used in successive approximation converters

RGB - acronym for "red-green-blue": a video display standard in which three separate signals (red, green, and blue) are used to transmit image information

RS-170 - the encoding standard for 60-Hz black-and-white television signals used in most monochrome video equipment

RS-343 - similar to RS-170, except that it provides high-resolution color information for computer video applications

RSSI - acronym for "Received Signal Strength Indicator" : a signal or circuit that indicates the strength of the incoming (received) signal in a receiver

sample and hold (S/H) circuit - a circuit that acquires an analog voltage and stores it temporarily in a capacitor; also referred to as a sample-and-hold amplifier (SHA)

SECAM - a video standard used in China, Russia, and France that employs sequential color and memory

sense - to measure the resulting current or voltage; see also "force" and "force/sense"

sensitivity - a measure of the minimum change in an input signal that an instrument can detect

settling time - the time required for a device or circuit's output voltage to settle and remain within a specified tolerance around the final value every time the output changes

shmoo plot - 1. a plot of pass/fail test results that involves pairs of test parameters such as frequency vs. voltage, or voltage vs. temperature; 2. a one-axis or two-axis pass/fail plot of a series of measurements

shutdown - the termination of the running of an operating system

sigma-delta converter - an ADC that uses a single-bit quantizer with a very high sampling rate combined with a single-bit DAC in a feedback loop

signal-to-noise ratio (SNR) - the ratio of total signal to total noise expressed in decibels (dB); SNR = 20 log (Signal RMS / Noise RMS)

signal conditioner - device placed between a signal source and a readout instrument to change the signal

SINAD - acronym for "Signal to Noise and Distortion": the ratio of total signal to the sum of noise and harmonics; SINAD = 20 log (Signal RMS / [Noise + Harmonics]RMS)

sink current - the amount of conventional current flow into a DUT pin with a pull-up load

sink voltage - the voltage at a DUT pin acting as a current sink.

skew - 1. an observed difference in time between two events that occur simultaneously; 2. the effect of different propagation delays along an electrical path or channel

slew rate - the rate of change of the op amp's voltage output over time when its gain is set to unity (Gain =1)

snubber - a device that suppresses voltage transients

SOC - acronym for "System on a Chip": a monolithic integrated circuit that contains all the necessary circuits that make up a complete system

source current - the amount of conventional current flow out of a DUT pin with the pull-down load

source voltage - the voltage at a DUT pin that is acting as current source

span - the full-scale analog input range of a device

spike - a transient disturbance of an electrical circuit caused by, for example, load variations on the AC power line

spooling - the process of queuing tasks or jobs such as background printing

stability - the ability of an instrument or sensor to maintain a consistent output when a constant input is applied

STDF - acronym for "Standard Test Data Format": a standard output format for electrical test results which can be subjected to post-processing and statistical analyses using various tools

stimulus - an input signal that initiates action or reaction in a circuit; an input signal used for circuit excitation

strobe - a pulse or signal that clocks one or more digital data into a latch or memory circuit

sub-pixel resolution - an imaging technique that can yield a measurement that has a spatial resolution of less than one pixel

successive approximation - a technique used in analog-to-digital conversion wherein a reference DAC is fed with a series of progressively finer digital data until its output matches the analog input, at which point the input data to the reference DAC becomes the output of the ADC

surge - a sudden change (usually an increase) in the voltage of a power line; a surge is similar to a spike, but it lasts longer

susceptibility - a measure of a device or system's ability to prevent undesirable responses when subjected to electromagnetic radiation

swing - the maximum output voltage that an operational amplifier can deliver without saturation or clipping for a given load and operating supply voltage

sync - the portion of a video signal that indicates either the end of a line or the end of a field of video information

test protocol - a sequence of control operations required to perform a test

test specifications - a document defining the operational parameters of a device

tester - the equipment used for electrically testing semiconductor devices to screen out all units that are not shippable to customers

test site - a position on a test head where a device-under-test (DUT) is tested

test site number - a number that identifies a test site location on the test head

thermocouple - a temperature sensor formed by the junction of two dissimilar metals which has a voltage output proportional to the difference in temperature between the hot junction and the lead wire (cold) junction

thermostat - a device or circuit that indicates whether a measured temperature is above or below a particular temperature threshold or trip point

throughput rate - the maximum repetitive rate at which a data converter can operate within a specified accuracy

time-out error - an error that occurs after the maximum time interval for an expected event to take place has lapsed

tolerance - the amount of deviation that a device's output parameter is allowed to exhibit from its nominal or target value

total harmonic distortion (THD) - 1. a measure of a signal's distortion content, represented by the harmonics of that signal expressed as a percentage of the signal amplitude; 2. the ratio of the rms sum of the first few (2nd to 6th) harmonic components of a device's output to its fundamental value, usually expressed in dB

trace - to monitor the execution of a program and report the sequence of actions carried out

transceiver - a device that contains both a transmitter and receiver.

transconductance amplifier - an amplifier that converts a voltage to a current

transimpedance amplifier - an amplifier that converts a current to a voltage

tristate - a high-impedance state for a device output that is not in use

uniform resource locator (URL) - a string of characters that uniquely identifies each web site

unipolar mode - the mode of operation of a converter wherein the zero to full-scale analog value is of single polarity only

unipolar offset - the deviation of the ADC's actual first transition from its ideal level, i.e., 1/2 LSB above the analog common

validation - a "post-silicon" process that uses special purpose test hardware to prove that a product meets the design intent

verification - a "pre-silicon" test process done during development to gain confidence that a new design will produce the expected results

voltage-controlled oscillator (VCO) : an oscillator whose output frequency is proportional to its input voltage

vertical sync - the portion of a video signal that indicates the end of a field of video information

video encoder - a device that converts RGB video into composite video

voltage doubler - a capacitor charge pump circuit which produces an output voltage that is twice the input voltage

voltage-to-frequency converter (VFC) - a device that converts an analog input voltage into a sequence of digital pulses with a frequency that is proportional to the input voltage

wafer - a thin, polished slice of monolithic semiconductor on which an array of die circuits are fabricated

wafer level burn-In (WLBI) - a temperature/bias reliability stress test conducted on devices that are still on a wafer, in contrast with conventional burn-in which is performed on finished IC's

wafer map - a plot of the viable dice on a wafer showing pass/fail information, parameter variations, or some other characteristics

waveform - the succession of signal levels applied to the DUT pin after combining pattern and timing information

window comparator - a device, usually consisting of a pair of voltage comparators, whose output indicates whether the input signal is within the voltage range bounded by a lower and upper threshold

yield - the proportion of good devices in a lot or run

zero voltage crossing (ZVC) - the point in a plot of a voltage quantity against another parameter at which the voltage value equals zero

ZIF - acronym for "Zero Insertion Force" : a class of IC sockets that does not require device insertion, instead achieving contact with the IC pins through a clamping system that's controlled by a small lever on the side of the socket

See Also: Electrical Test

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