L

latch-up

An undesirable phenomenon in which either a PNPN or an NPNP thyristor-type parasitic structure suddenly turns to an "on" state, thereby bypassing or shorting out portions of an IC. To prevent latch-up, Intersil uses either epitaxy layers to avoid diffused pockets or a retrograde P-well, which is designed to specifically avoid latch-up. See epitaxy

LCC

Leadless Chip Carrier. A surface-mounted package having metallized contacts (terminals) at its periphery. Usually made of ceramic material.

LDD

Lightly Doped Drain. See doping and drain.

leadframe

A stamped or etched metal frame, usually connected to the bonding pads of a die by wire bonding, that provides external electrical connections for a packaged electrical device.

LED

Light-Emitting Diode. A semiconductor P-N junction diode that emits light under forward-bias conditions. The wavelength of the emitted light is a function of the semiconductor material. The crystal structure of silicon does not provide useful levels of light emission, but the structure of GaAs does, with an infrared emission wavelength.

library

The term used to designate the collection of representations required by the various design tools. These representations, such as symbol, simulation model, layout abstract, transistor schematic, are used by the different tools in the design system to create or analyze some portion of the IC or otherwise aid in the design process. Creating a design library is effectively inserting the fabrication technologies into the design system in a form that allows designers to create circuits in the most efficient manner.

linear

(1) Having an output that varies in direct proportion to the input. (2) A ratio in which a change in one of two related quantities is accompanied by a directly proportional change in the other.

linear device

An amplifying-type, analog device with a linear input/output relation, as opposed to a non-linear, digital device, which is either completely "on" or completely "off" over large ranges of input signals.

linear integrated circuit

A circuit whose output is an amplified, linear version of its input or whose output is a predetermined variation of its input. A class of integrated circuits that process analog information expressed as voltages or currents.

lithography

The transfer of a pattern or image from one medium to another, as from a mask to a wafer. If light is used to effect the transfer, the term "photolithography" applies. "Microlithography" refers to the process as applied to images with features in the micrometer range. See also aligner, mask, stepper, and X-ray lithography.

LOCOS

LOCalized Oxidation Of Silicon. See silicon.

logic

Mathematical treatment of formal logic in which a system of symbols is used to represent quantities and relationships. AND, OR and NOT are examples of symbols of logical functions. Each function can be translated into a switching circuit, or gate. Since a switch (or gate) has only two states--open or closed--it makes possible the application of binary numbers for solution of problems. The basic logic functions obtained from gate circuits is the foundation of computing machines. Intersil manufactures a broad line of logic circuits in CMOS technology.

logic-level MOSFET

A MOSFET with low operating voltages that can operate directly from a microprocessor or 5V logic instead of from the 10V usually supplied by IC buffer stages. Logic-level MOSFETs can eliminate the need for buffers. See MOSFET.

logic optimization

Optimization of logic circuits for either area or speed using a tool such as the Synopsys Design Compiler.

logic synthesis

Synthesis of gate level logic circuits from behavioral descriptions using a tool such as the Synopsys Design Compiler.

LPCVD

Low Pressure Chemical Vapor Deposition. See deposition.

LSI

Large-Scale Integration. Integrated circuits containing between 100 and 5000 gate equivalents, or 1000 to 16,000 bits of memory. Over the years, integration levels have progressed from SSI (small-scale integration), MSI (medium-scale integration), and LSI, to today's VLSI (very-large scale integration).

Layout Versus Schematic. Compares the electrical design (schematic) with the physical design (layout) to ensure what will be built is what was designed.