Electronics glossary — Letter U

28 terms starting with U

UADSL

universal ADSL

UCIe

Universal Chiplet Interconnect Express – an open standard for die-to-die connections between chiplets within a single package, allowing chiplets from different vendors to be combined.

UDP

user datagram protocol

UG

Used to describe coaxial connectors that are made to a Government Specification.

uhf

Ultra High Frequency – A Federal Communications Commission designation for the band from 300 to 3000 MHz on the radio spectrum. In television, channels 14 to 83, or 470 to 890 MHz.

UL

Underwriters’ Laboratories, Inc. An independent laboratory that tests equipment to determine whether it meets certain safety standards when properly used.

ultrahigh frequency

UHF – A Federal Communications Commission designation for the band from 300 to 3000 MHz on the radio spectrum. In television, channels 14 to 83, or 470 to 890 MHz.

ultrasonic bond

A joining of materials achieved by the scrubbing action and energy transfer of a tool vibrating at an ultrasonic frequency. Attaching leads to pads on silicon devices, and achieving bonds between dissimilar metals are two common applications of this process. See also ultrasonic welding.

ultrasonic welding

Process using vibratory mechanical pressure at ultrasonic frequencies (20 to 40 kHz) to provide heat for welding some types of thermoplastics. See also ultrasonic bond.

ultraviolet curing

Process of accomplishing complete cross-linkage of a polymer coating or other product using ultraviolet light on the work piece.

Ultraviolet Degradation

The degradation caused by long-time exposure of a material to sunlight or other ultraviolet rays.

umbilical connector

Used to connect ground support cables to a rocket or missile, and is then disconnected from the missile at the time of launching.

UMTS

Universal mobile telecommunications system. The name of the third-generation mobile phone standard promoted by ETSI for use in Europe.

Uncertainty

The degree to which a parameter or characteristic cannot be specifically determined.

Undershoot

Transient change in a converter output voltage that does not meet the lower limit of the voltage accuracy specificiation. Typically occurs at converter turn on/off or with some step change in output load or input line. Also see Voltage Accuracy.

Undervoltage lockout

Design feature that helps regulate the quality of the output voltage by turning the device OFF in response to supply voltages that fall below its UVLO level. Raychem power switches have a nominal UVLO threshold of 2.5V.

Underwriters Laboratory

UL – Independent organization that conducts safety testing of products to established standards.

U-NII

Unlicensed national information infrastructure spectrum, 5.8-GHz.

Uninterruptible Power Supply

UPS – Power supply that will continue to operate after the loss of AC input power.

UNIX

A popular operating system originally developed by Bell Labs.

Upconverter (Mixer)

A mixer whose desired output signal, called the RF signal, is the sum of the incident baseband (sometimes called the IF) and LO signals.

UPS

Uninterruptible Power Supply – Power supply that will continue to operate after the loss of AC input power.

UTC

Coordinated Universal Time

UTM

Universal Transverse Mercator. An almost worldwide coordinate projection system using north and east distance measurements from reference point(s). UTM is the primary coordinate system used on U.S. Geological Survey topographic maps.

UTP

Unshielded twisted pair cable. Cable made from pairs of wires which have been twisted together.

UV

Ultraviolet.

UVLO

Design feature that helps regulate the quality of the output voltage by turning the device OFF in response to supply voltages that fall below its UVLO level. Raychem power switches have a nominal UVLO threshold of 2.5V.

UWB

Ultra-Wideband – a short-range radio technology that uses very wide bandwidth pulses for precise location and ranging, used in digital car keys, asset tracking and device finding.