Semiconductor Glossary - U

• µ

micron - see letter M in the glossary

• 235U

Uranium-235

• 238U

Uranium-238

• U

Uranium

• UAI

Use As Is

• UAQI

Uniform Air Quality Index

• UART

Universal Asynchronous Receiver Transmitter

• UCL

Upper Control Limit

• UCR

Unit Carcinogenic Risk

• UDCS

Unified Document Control System (and ADCS: Advanced Document Control System) Information System used to create, modify, validate, store and distribute the company official documents such as product specifications, purchasing specifications, customer specific specifications, SOP, design rules. ADCS is the new software tool generation which replaced UDCS.

• UEL

Upper Explosive Limit

• UF

Uncertainty Factor

• UFBGA

Ultra thin Fine pitch Ball Grid Array Total height 1.0 max.

• UFL

Upper Flammable Limit

• UHF

Ultra High Frequency

• UID

1) U-Interface Device 2) Unique Identification Device

• UK

United Kingdom

• UKASS

UK Association of Suggestions Scheme

• UL

Underwriters Laboratories

• ULAS

Uncommitted Logic Array

• ULR

Uniform Resource Locator

• ULSI

Ultra Large Scale Integration An IC containing 10,000+ circuits.

• Ultrasonic Bonding

A wire bonding technique that utilizes ultrasonic energy and pressure to form the bond, without heat.

• UN/NA number

United Nations/North America number

• UN/EDIFACT

Electronic Data Interchange for Administration, Commerce and Transport

• Undercut

The lateral etching that occurs as the etching proceeds vertically.

• UNEP

United Nations Environment Program

• UNI

User Network Interface

• Unipolar

Refers to FET devices where current passes only through one type of semiconductor material (P or N) as it flows from input to output.UNSCH UNSCHeduled Orders for which a confirmed date has not been given to the customer.

• uP

Microprocessor

• UPC

Universal Product Code

• UPH

Units Per Hour Number of defect-free parts produced per hour worked.

• UPS

Uninterruptable Power Supply A power supply with backup batteries or standby generator and an automatic controller that ensures continuous supply even when the main power feed is interrupted.

• Uranium (U)

A rare heavy metal with an atomic number of 92. The most common atomic weight in naturally occurring uranium is 238. Other isotopes range from 234 to 239. Uranium is found in natural deposits in several parts of the world, principally as the oxide. The element was little used until about 1942 when it was discovered that Uranium-235 (the uranium isotope with an atomic weight of 235), which is present in natural uranium deposits at levels of 0.7%, could be employed as a fission fuel for the construction of nuclear reactors and weapons. This discovery led to todayis nuclear armaments and the nuclear industry.

• URCLK

Universal Transmitter Clock

• URL

Uniform Resource Locator A naming convention that uniquely identifies the location of a computer, directory, or file on the Internet. The URL also specifies the appropriate Internet protocol, such as HTTP, and so on.

• URT

Upper Respiratory Tract

• USART

Universal Synchronous/Asynchronous Receiver/Transmitter

• USB

Universal Serial Bus

• USDW

Underground Source of Drinking Water

• UST

Underground Storage Tank ST has defined an underground storage tank as a single-walled tank which is buried directly in the ground. UST's are a common source of contamination of soil because their contents leak out. The wall of UST's can corrode (because they are partially located below the water table, or the materials in the tanks are incompatible with the materials with which the tank is made, or there are stray electric currents in the ground, or for some other reason), or they can be crushed and opened at joints with pipes etc. (because, e.g., they are placed under a road over which pass heavy lorries), or it can simply be an issue of incorrect filling or emptying practices (overfilling, unhooking of filling pipes which are still filled with liquids, etc.). The risks of uncontrolled leaks can be minimized by using tanks with double walls, by installing them in vaults which can be inspected or in which can be inserted leak detection systems, by installing overfill controls, by monitoring them regularly for leaks, etc.

• Up time

The time that a piece of equipment is working - the opposite of down time.

• UTC

1)Universal Time Code 2) Universal Time Coordinated An international, highly accurate and stable uniform atomic time system.

• UTIL

Utility

• UUENCODE

Unix to Unix Encoding

• UV

Ultra Violet

• UV-A

Ultraviolet radiation-A (Alpha)range

• UV-B

Ultraviolet radiation-B (Besta) range

• UV-C

Ultraviolet radiation-C range

• UVLD

UltraViolet Lockout Device

• UVLO

Under Voltage LockOut

• UV-VAS

Ultraviolet - Visible Absorption Spectrum