COMPONENT MAINTENANCE MANUAL
IN 1502H RADAR INDICATOR
TM109102
3-6
May/01
Transistor Base Configurations
Figure 3-1 (Sheet 2 of 2)
D. Integrated Circuits
(1) Series 54/74 Integrated Circuits
Type-number identification is becoming increasingly complex for the 54/74 series of
integrated circuits, which were originally referred to as TTL chips. Today, many
different type number may apply to chips that perform the same function, although
specifications (temperature, speed, power, etc.) and interior configurations may be
different. Usually the only difference in the type numbers involves the alpha
characters immediately following the 54/74 designation.
Consider the quadruple D-type flip-flop chip 74LS175. This logic circuit may be
manufactured with type numbers 54175, 54S175, 54LS175, 54AS175, 54ALS175,
74175, 74S175, 74LS175, 74AS175 and 74ALS175. These devices all perform the
same logic function, but each has a different specification, different internal
construction and are not interchangeable in all circuit applications. However, the same
pin arrangement and IC diagram are used for all these devices. Most chips are
available in both 54 series and 74 series type numbers. The 54 series has an
operating temperature specification of -55
°
C to 125
°
C and the 74 series has a
temperature specification of
0°
C to 70
°
C. Table 3-4 describes the primary differences
corresponding to the alpha characters in the type number.
The document reference is online, please check the correspondence between the online documentation and the printed version.
