Electronic Glossary

Underwriter’s Laboratories, Inc., a corporation supported by some underwriters for the purpose of establishing safety standards on types of equipment or components.

UL 94, the Standard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances testing, is a plastics flammability standard released by Underwriters Laboratories (UL) of the United States. The standard determines the material’s tendency to either …

As with fine-pitch, a term whose value depends on the date of the definition. The term now (arguably) applies to surface mount packages with a center-to-center lead distance of 0.4mm (0.016in) or less. Also see Fine Pitch.

Underfill is typically a polymer or liquid epoxy that applied to the printed circuit board (PCB) after the board has been subjected to the reflow soldering process in PCB assembly. The underfill is dispensing onto a corner or along the …

Ultra Thin Quad Flat Non-Leaded Package (UQFN or UTQFN) is a very small and thin square-shaped or rectangular surface-mount plastic package with no leads. Instead of leads, it uses metal pads around the periphery of the package body for electrical …

What’s USB?   Universal Serial Bus (USB) is an industry standard that establishes specifications for cables and connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad variety of USB hardware exists, …

USON is Plastic Ultra-Thin Small Outline No-lead (SON) Package defined by JEDEC, slightly smaller than WSON. It is a surface mounting device (SMD) with 4-16 pins, and the pitch has 0.5mm, 0.65mm (DNP, TI) , and 1.0mm (NLB, TI). Due to …

What’s UTDFN Package?   Ultra Thin Dual Flat No-lead (UTDFN) package is a very small and thin square-shaped or rectangular surface-mount plastic package with no leads. Instead of leads, it uses metal pads along two sides of the package body …

Polymerizing, hardening, or cross linking a low molecular weight resinous material in a wet coating ink using Ultra Violet (UV) light as an energy source.

What’s Volt-Ampere?   A volt-ampere (SI symbol: V⋅A or V A; also VA) is the unit used for the apparent power in an electrical circuit. The apparent power equals the product of root mean square voltage and root mean square …