Integrated circuit

Intel D4040, an early microprocessor, the first computer processor in a single integrated circuit

Integrated circuit of Atmel Diopsis 740 System on Chip showing memory blocks, logic and input/output pads around the periphery

Introduction

An integrated circuit (more often called an IC, microchip, silicon chip, computer chip, or chip) is a piece of specially prepared silicon (or another semiconductor) into which a very complex electronic circuit is etched using photographic technique. Silicon chips can contain computer processors, memory and special devices. The chip is very fragile and so is normally surrounded by a tough plastic package, and electrical contact with the chip are provided through metal legs sticking out of the package. There are two main advantages of ICs over discrete circuits: cost and performance. Cost is low because the ICs are printed as a complete unit by photolithography and not constructed as one transistor at a time. Performance is higher since the components switch quickly, consuming little power. ICs work as they are designed. Let's suppose that you designed a chip as a calculator, which only works as a calculator.

Invention

An integrated circuit was independently co-invented by Jack Kilby and Robert Noyce around the same time in late 1950's.

Generations

name	period	numbers of transistors on each chip(approximately)
SSI(Small-Scale Integration)	early 1960s	one chip contains only a few transistors
MSI(Medium-Scale Integration)	late 1960s	hundreds of transistors on each chip
LSI(Large-Scale Integration)	mid 1970s	tens of thousands of transistors per chip
VLSI(Very Large-Scale Integration)	early 1980s ~ present(?)	about hundreds of thousands of transistors ~ several billion transistors
ULSI(Ultra-Large Scale Integration)	not yet(?)	more than 1 million transistors

※The difference between VLSI and ULSI is obscure.

Classification

Side view of dual in-line package (DIP).

Picture of Plastic Quad Flat Pack(PQFP).

Integrated circuits can be classified into DIP(Dual in-line package), PLCC(Plastic leaded chip carrier), TSOP(Thin small-outline package), PQFP(Plastic Quad Flat Pack) and etc by chip package type.

Other pages

Microprocessor