ATE Glossary [A - D]

Glossary pages: [ A - D ] , [ E - H ] , [ I - P ] and [ Q - Z ]

Active Load – A form of load that can be switched into circuit using an active device. In some circumstances it may act as either a pull up or a pull down.

ADC – Analogue to Digital Converter. A device that converts an analogue value into a digital representation of its value.

AOI – Automated Optical Inspection. This may also be referred to on occasions as Automatic Optical Inspection. It is an inspection tool using cameras that optically scans a board comparing the information with that of known good boards to detect errors in manufacture. Typically these may be incorrect components, incorrectly placed components, missing components and dry joints.

APG - Automatic Programme Generator. A computer programme that generates the vectors or other information required for a test programme.

ATE – Automatic Test Equipment. A test equipment system that is computer driven and able to run test programmes to test the unit under test.

Autorange – The ability of an instrument to automatically choose the optimum range of the instrument for the magnitude of the measurement being made.

AXI – Automated X-ray Inspection. A form of inspection that uses X-Rays and in this way joints under components such as ball grid array chips can be seen.

Bed of nails – A test fixture used to hold a board under test. It has contact pins or “nails” that connect with the relevant nodes on the board. As they generally have a large number of contact pins they can seem like a bed of nails, thereby giving them their name.

Boundary Scan – A test methodology that uses shift registers in the output connections of integrated circuits, one IC often is connected to the next. A data pattern is passed through the chain and the observed returned data stream affected by the circuit conditions gives an indication of any faults present. The system is defined under IEEE standard 1149.1 and is also often known as JTAG (Joint Test Action Group).

BIST – Built In Self Test. A facility contained within a circuit, module or unit that enables it to test itself. It will typically consist of some additional circuitry and software.

BIT – Built In Test. Another name for BIST

BITE – Built In Test Equipment. This refers to the circuitry or “equipment” that is built in to a unit of assembly to enable to undergo a self test.

CMMR – Common Mode Rejection Ratio. It is a measure of the ability of a test instrument to reject interference that is common to both of its measurement input terminals. It is expressed in decibels and it is the ratio of the actual or common signal level appearing on the two input terminals together to the measured level.

Combinational Tester – A test system or tester that uses a variety of test approaches. These may include in-circuit test as well as boundary scan and functional test.

Counter – An instrument that measures or counts events. Often a frequency meter is called a frequency counter because it counts the number of cycles in a given period.

Coverage – See Fault Coverage.

DBT – Defect Based Test. A test methodology that looks at the defect densities and overall layout and devises tests that are most likely to uncover the likely defects.

DFM – Design For Manufacture. A methodology of ensuring that a device or unit can be manufactured easily and cost effectively. The elements of manufacturability must be included in the design from the concept stages.

DFT – Design For Test. A methodology of ensuring that a device or unit can be tested effectively during manufacture. The elements of testability must be included in the design from the concept stages.

Diagnostic tests – Tests that are undertaken or available to locate a problem of failure that has occurred in the main production or calibration test.

DPM – Defects Per Million. A defect level expressed in terms of the number of defects that would be found in a million samples.

DUT – Device Under Test. The item that is the target or focus of a test. It may sometimes be called the CUT or Circuit Under Test.