TABLE 79.1 Defining Truth Tables for Logic Gates 1-Input Function 2-Input Functions Input Output Inputs Output Functions NOT A B AND OR NAND NOR XOR XNOR 0 0101 1110 1000 0110 TABLE 79.2 Logic Families and Subfamilies Family and Subfamily Description Transistor-transistor logic Standard ttl Low-power TTL High-speed TTL Schottky TTL 74ASXX dvanced Schottky TTL dvanced low-power Schottky TTL Fast TTL andard CMOS Standard CMOS using TTL numbering syster High-speed CMOS High-speed CMOS-TTL compatible Fast CMOS-TTL compatible 74ACxX dvanced CMOS 74ACTXX Advanced CMOS--TTL compatible CMOS-TTL compatib ECL (or CML Emitter-coupled (current-mode)logic Standard eCL 10Hxx High-speed ECL IC Logic Families and Subfamilies The integrated circuit logic families actually consist of several subfamilies of ICs that differ in various perfor- nance characteristics. The TTl logic family has been the most widely used family type for applications that employ small-scale integration(SSI)or medium-scale integration(MSI) integrated circuits. Lower power consumption and higher levels of integration are the principal advantages of the CMOS family. The ECL family is generally used in applications that require high-speed switching logic. Today, the most common device lumbering system used in the TTL and CMOS families has a prefix of 54 (generally used in military applications and having an operating temperature range of-55 to 125.C)and 74(generally used in industrial/commercial plications and having an operating temperature range of 0 to 70oC). Table 79.2 identifies various logic families and su TTL Logic Family The Ttl family has been the most widely used logic family for many years in applications that use SSI and MSI. It is relatively fast and offers a great variety of standard chips The active switching element used in all TTL family circuits is the npn bipolar junction transistor(BjT) e 2000 by CRC Press LLC© 2000 by CRC Press LLC IC Logic Families and Subfamilies The integrated circuit logic families actually consist of several subfamilies of ICs that differ in various perfor￾mance characteristics. The TTL logic family has been the most widely used family type for applications that employ small-scale integration (SSI) or medium-scale integration (MSI) integrated circuits. Lower power consumption and higher levels of integration are the principal advantages of the CMOS family. The ECL family is generally used in applications that require high-speed switching logic. Today, the most common device numbering system used in the TTL and CMOS families has a prefix of 54 (generally used in military applications and having an operating temperature range of –55 to 125°C) and 74 (generally used in industrial/commercial applications and having an operating temperature range of 0 to 70°C). Table 79.2 identifies various logic families and subfamilies. TTL Logic Family The TTL family has been the most widely used logic family for many years in applications that use SSI and MSI. It is relatively fast and offers a great variety of standard chips. The active switching element used in all TTL family circuits is the npn bipolar junction transistor (BJT). The transistor is turned on when the base is approximately 0.7 V more positive than the emitter and there is a sufficient amount of base current flowing. The turned on transistor (in non-Schottky subfamilies) is said to TABLE 79.1 Defining Truth Tables for Logic Gates 1-Input Function 2-Input Functions Input Output Inputs Output Functions A NOT A B AND OR NAND NOR XOR XNOR 0 1 0 0 0 0 1 1 0 1 1 0 0 1 0 1 1 0 1 0 1 0 0 1 1 0 1 0 1 1 1 1 0 0 0 1 TABLE 79.2 Logic Families and Subfamilies Family and Subfamily Description TTL Transistor-transistor logic 74xx Standard TTL 74Lxx Low-power TTL 74Hxx High-speed TTL 74Sxx Schottky TTL 74LSxx Low-power Schottky TTL 74ASxx Advanced Schottky TTL 74ALSxx Advanced low-power Schottky TTL 74Fxx Fast TTL CMOS Complementary metal-oxide semiconductor 4xxx Standard CMOS 74Cxx Standard CMOS using TTL numbering system 74HCxx High-speed CMOS 74HCTxx High-speed CMOS—TTL compatible 74FCTxx Fast CMOS—TTL compatible 74ACxx Advanced CMOS 74ACTxx Advanced CMOS—TTL compatible 74AHCxx Advanced high-speed CMOS 74AHCTxx Advanced high-speed CMOS-TTL compatible ECL (or CML) Emitter-coupled (current-mode) logic 10xxx Standard ECL 10Hxxx High-speed ECL