Description and Attributes of the Logic Families

Here is a list of the various logic families that are used to make various integrated circuits such as processors and inexpensive DIP chips. This list contains various information on each logic family such as advantages, disadvantages, operating conditions, etc. More information will be added to this list occasionally.

BiCMOS (Bipolar Complementary Metal-Oxide-Semiconductor Logic) - Uses CMOS transistors and bipolar-junction transistors (BJT)

CML (Current-Mode Logic) - See ECL

CMOS (Complementary Metal-Oxide-Semiconductor) - Uses a combination of p-type and n-type MOSFETs; contains PMOS and NMOS transistors

• Advantages
  • High noise immunity
  • Low static power consumption
• Operating Conditions
  • Temperature range - -55°C to 125°C

COS-MOS (Complementary-Symmetry Metal-Oxide-Semiconductor) - See CMOS

CSEF (Current-Switch Emitter-Follower Logic) - See ECL

CSL (Current-Steering Logic) - See ECL

DCTL (Direct-Coupled Transistor Logic) - Uses transistors and resistors; the input bases are connected directly to the collector outputs; transistors are heavily overdriven

• Advantages
  • Less components than RTL logic
  • Less expensive than RTL logic
  • Easier to make than RTL logic
  • Reduced saturation voltage of the output transistors
• Disadvantages
  • Susceptibility to ground noise
  • Smaller signal levels
  • Requires matched transistor characteristics

DL (Diode Logic) - Uses diodes and resistors

• Advantages
  • Simple
• Disadvantages
  • Only AND and OR gates can be made
• Operating Conditions
  • Temperature (Germanium diode) - 0°C to 85°C
  • Temperature (Silicon diode) - 0°C to 125°C

DRL (Diode-Resistor Logic) - See DL

DTL (Diode-Transistor Logic) - Uses diodes, transistors, and resistors

• Advantages
  • Increased fan-in

ECL (Emitter-Coupled Logic) - Uses an overdriven bipolar-junction transistor (BJT) differential amplifier; transistors never in saturation; input impedance is high; output resistance is low

• Advantages
  • Low gate delays
  • High fan-out
• Disadvantages
  • Continuously draws current

GTL (Gunning Transceiver Logic) - Uses a pair of NMOS transistors in series

I2L (Integrated Injection Logic) - Uses multiple collector bipolar-junction transistors (BJT); operates by current instead of voltage

• Advantages
  • High noise immunity
• Logic
  • High - 0.7V
  • Low - 0.2V

IIL (Integrated Injection Logic) - See I2L

MTL (Merged Transistor Logic) - See I2L

NMOS (N-type Metal-Oxide-Semiconductor Logic) - Uses n-type MOSFETs

• Disadvantages
  • Susceptible to noise

PMOS (P-type Metal-Oxide-Semiconductor Logic) - Uses p-channel MOSFETs

TTL (Transistor-Transistor Logic) - Uses bipolar-junction transistors (BJT) and resistors; inputs are the emitters of multiple-emitter transistors; current-sinking logic

• Disadvantages
  • Slower than others
• Operating Conditions
  • Temperature (5400 series) - -55°C to 125°C
  • Temperature (7400 series) - 0°C to 70°C
  • Voltage - 5VDC
• Attributes
  • Gate Propagation Delay - 10ns
  • Power Dissipation - 10mW per gate
• Logic
  • High (Input) - 2.2V to 5V
  • Low (Input) - 0V to 0.8V
  • High (Output) - 2.6V to 5V
  • Low (Output) - 0V to 0.4V
• Subtypes
  • Advanced-Schottky (AS)
  • Fast (F)
  • High-speed TTL (H)
  • Low-power Schottky TTL (LS)
  • Low-power TTL (L)
  • Low-voltage TTL (LVTTL)
  • Schottky TTL (S)