Integrated Circuits Logic Families

What is Integrated Circuit explain?

Integrated circuits (IC), also called microelectronic ckt, microchips, or chips, an assembly of electronics component, fabricated as a single unit, in which miniaturized active devices (e.g., transistors and diodes) and passive devices (e.g., capacitors and resistors)

What are integrated circuits used for?

The integrat-ed circuit, or IC, is small chip that can function as an amplifier, oscillator, timer, microprocessor, or even computers memory. An IC is a small wafer, usually made of silicon, that can hold anywhere from 100s to millions of transistor, resistors, and capacitors.

What is Integrated Circuit and its types, when was it developed?

In August 1959, Noyce formed at Fairchild a group to develop integrated circuits. On May 26, 1960, this group, led by Jay Last, produced the first planar integrated circuit. This prototype was not monolithic – two pairs of its transistors were isolated by cutting a groove on the chip, according to the patent by Last.

ICs Notes

Integrated Circuits 

• Integrated circuits (ICs) are chips, pieces of semiconductor material, that contain all of the transistors, resistors, and capacitors necessary to create a digital circuit or system.
• The first ICs were fabricated using Ge BJTs in 1958.
  • Jack Kirby of Texas Instruments, Nobel Prize in 2000
  • Robert Noyes of Fairchild Semiconductors fabricated the first Si ICs in 1959.

Integration Levels:

• SSI Small scale integration [12 gates/chip]
• MSI Medium scale integration [100 gates/chip]
• LSI Large scale integration [1K gates/chip]
• VLSI Very large scale integration [10K gates/chip]
• ULSI Ultra large scale integration [100K gates/chip]

Moore's Law:

• A prediction made by Moore (a co-founder of Intel) in 1965: “… a number of transistors to double every 2 years.”

2. Characteristics of digital circuits

• Fan in:
  • Fan in is the number of inputs connected to the gate without any degradation in the voltage level.
• Fan out:
  • Fan out specifies the number of standard loads that the output of the gate can drive without impairment of its normal operation
• Power dissipation:
  • Power dissipation is a measure of power consumed by the gate when fully driven by all its inputs.
• Propagation delay:
  • Propagation delay is the average transition delay time for the signal to propagate from input to output when the signals change in value. It is expressed in ns.
• Noise margin:
  • It is the maximum noise voltage added to an input signal of a digital circuit that does not cause an undesirable change in the circuit output. It is expressed in volts.

TTL and CMOS | Characteristics of families

Complementary metal–oxide–semiconductor, also known as complementary-symmetry metal–oxide–semiconductor, is a type of metal–oxide–semiconductor field-effect transistor fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSFETs for logic functions. Wikipedia

TTL and CMOS

Fan Out | Power Dissipation | Noise Margin | Power Delay

Transistor–transistor logic (TTL) is a logic family built from bipolar junction transistors. Its name signifies that transistors perform both the logic function (the first "transistor") and the amplifying function (the second "transistor"), as opposed to resistor–transistor logic (RTL) or diode–transistor logic (DTL).

Fan out to Power Delay

Types of TTL:

• Standard TTL
  • typical gate propagation delay of 10ns and a power dissipation of 10 mW per gate, for a power–delay product (PDP) or switching energy of about 100 pJ
• Low-power TTL (L)
  • slow switching speed (33ns)
  • reduction in power consumption (1 mW) (now essentially replaced by CMOS logic)
• High-speed TTL (H)
  • faster switching than standard TTL (6ns)
  • but significantly higher power dissipation (22 mW)
• Schottky TTL (S)
  • used Schottky diode clamps at gate inputs to prevent charge storage and improve switching time. A Schottky diode has a very low forward-voltage drop of 0.15–0.45V approx (silicon diode has a voltage drop of 0.6–1.7V). This lower voltage drop can provide higher switching speed.
  • Faster speed of (3ns) but had higher power dissipation (19 mW)
• Low-power Schottky TTL (LS)
  • used the higher resistance values of low-power TTL and the Schottky diodes to provide a good combination of speed (9.5ns) and reduced power consumption (2 mW), and PDP of about 20 PJ.