Solution:

What is an integrated circuit?

• A monolithic integrated circuit (IC) is an electronic circuit that is constructed entirely on a single small chip of silicon.

All the components that make up the circuit—transistors, diodes, resistors, and capacitors—are an integral part of that single chip. Fixed-function logic and programmable logic are two broad categories of digital ICs.

In fixed-function logic devices, the logic functions are set by the manufacturer and cannot be altered. Figure shows a cutaway view of one type of fixed-function IC package with the circuit chip shown within the package.

Points on the chip are connected to the package pins to allow input and output connections to the outside world.

Integrated circuit (IC) packages:

• Integrated circuit (IC) packages are classified according to the way they are mounted on printed circuit boards (PCBs) as either through-hole mounted or surface mounted.

• The through-hole type packages have pins (leads) that are inserted through holes in the PCB and can be soldered to conductors on the opposite side.

• The most common type of through hole package is the dual in-line package (DIP) shown in Figure(a).

• Another type of IC package uses surface-mount technology (SMT). Surface mounting is a space-saving alternative to through-hole mounting.

• The holes through the PCB are unnecessary for SMT. The pins of surface-mounted packages are soldered directly to conductors on one side of the board, leaving the other side free for additional circuits.

• Also, for a circuit with the same number of pins, a surface-mounted package is much smaller than a dual in-line package because the pins are placed closer together.

• An example of a surface mounted package is the small-outline integrated circuit (SOIC) shown in Figure(b).

• Various types of SMT packages are available in a range of sizes, depending on the number of leads (more leads are required for more complex circuits and lead configurations). Examples of several types are shown in Figure.

• As you can see, the leads of the SSOP (shrink small-outline package) are formed into a “gull-wing” shape. The leads of the PLCC (plastic-leaded chip carrier) are turned under the package in a J-type shape.

• Instead of leads, the LCC (leadless ceramic chip) has metal contacts molded into its ceramic body. The LQFP (low-profile quad flat package) also has gull-wing leads.

• Both the CSP (chip scale package) and the FBGA (fine-pitch ball grid array) have contacts embedded in the bottom of the package.