Although some integrated circuits are available in cylindrical metal cases, such as the TO-5 enclosures used to package discrete transistors, the majority of modern l Cs are packaged in the case type called a dual ill-line package (DIP). These rectangular cases have rigid metal tabs. called pins. that protrude from along each side of the package (see Figure 6-25). Each pin is electrically connected to one of the C pads and therefore serves as a terminal to which external circuit connections can be made. The package can be conveniently inserted into a plug board for experimentation or into holes drilled in a printed circuit board. DIP packages are available with several standard numbers of pins ranging from 4 to 64. Integrated circuits are also packaged in “flattop” form, where the pins protrude straight out from the case instead of at right angles to it. Figure 6-25 shows the standard DIP pin numbering system used by manufacturers to identify specific terminals and in schematic diagrams. Note that a groove. or dot on one end of the case identifies the top and that numbering proceeds down the left side and up the right side. . Like discrete transistors and diodes, integrated circuits are given numbers for identification purposes. However. the numbers do not have standard prefixes such as IN or EN. A particular integrated circuit may be’ produced by several different manufacturers and the identification number. which is usually printed on the case,
will have certain additional letters or codes to identify the manufacturer. For example, the 741 monolithic IC operational amplifier is manufactured by RCA as a CA741 and by National Semiconductor as an LM741
