Transistor-transistor logic

Transistor–Transistor Logic (TTL) is a class of digital circuits built from transistors and resistors. It is called transistor–transistor logic because the logic function (e.g., AND) and amplification is performed by transistors. There are a lot of integrated circuits with TTL technology. They are used in many applications such as computers, industrial controls, test equipment and instrumentation, synthesizers, etc.

Series Type

• Bipolar
  • 74 - the "standard TTL" logic family (long obsolete) had no letters between the "74" and the specific part number.
  • 74L - Low power (compared to the original TTL logic family), very slow (rendered obsolete by the LS-series)
  • H - High speed (rendered obsolete by the S-series, used in 1970s era computers)
  • S - Schottky (obsolete)
  • LS - Low Power Schottky
  • AS - Advanced Schottky
  • ALS - Advanced Low Power Schottky
  • F - Fast (faster than normal Schottky, similar to AS)
• CMOS
  • C - CMOS 4-15V operation similar to 4000 series
  • HC - High speed CMOS, similar performance to LS, 12nS
  • HCT - High speed, compatible logic levels to bipolar parts
  • AC - Advanced CMOS, performance generally between S and F
  • AHC - Advanced High-Speed CMOS, three times as fast as HC
  • ALVC - Low voltage - 1.65 to 3.3V, tpd 2nS
  • AUC - Low voltage - 0.8 to 2.7V, tpd<1.9nS@1.8V
  • FC - Fast CMOS, performance similar to F
  • LCX - CMOS with 3V supply and 5V tolerant inputs
  • LVC - Low voltage - 1.65 to 3.3V and 5V tolerant inputs, tpd<5.5nS@3.3V, tpd<9nS@2.5V
  • LVQ - Low voltage - 3.3V
  • LVX - Low voltage - 3.3V with 5V tolerant inputs
  • VHC - Very High Speed CMOS - 'S' performance in CMOS technology and power
  • G - Super high speeds at more than 1 GHz, 1.65V to 3.3V and 5V tolerant inputs, tpd 1nS (Produced by Potato Semiconductor)
• BiCMOS
  • BCT - BiCMOS, TTL compatible input thresholds, used for buffers
  • ABT - Advanced BiCMOS, TTL compatible input thresholds, faster than ACT and BCT