Degree of integration

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The level of integration called the absolute number of transistors in an integrated circuit ( English integrated circuit , IC). The degree of integration results from the integration density (number of transistors per unit area) and the chip size (area of ​​the IC).

The one VLSI

The degree of integration is also called logical complexity if logic gates are counted instead of transistors . A gate corresponds to about four transistors, as they are required in the prevailing CMOS technology for an unbuffered NAND gate with two inputs. Complex logic circuits such as Field Programmable Gate Arrays (FPGA) are often not implemented internally from individual gates but, for example, with lookup tables . In this case, gate equivalents are counted; H. the number of logic gates that would be necessary to implement this functionality. Complexity information in tag equivalents can only be compared to a limited extent between manufacturers, as there is a large scope for discretion with this information.

Degree of integration or logical complexity are very often characterized with terms such as SSI , MSISp , LSI or VLSI (more rarely also ULSI or SLSI ). SI stands for English scale integration , the respective prefix for the degree of integration, e.g. B. VLSI stands for English very-large-scale integration . These terms are defined inconsistently and very different numbers can be found in the literature. For processors that consist of more than 500 million transistors (e.g. AMD Opteron ), these terms have lost their meaning.

Development stages of the degree of integration of integrated circuits
Abbr. designation Complexity (gate equivalents)
typical interpretation Tanenbaum Texas Instruments
SSI small scale integration 10 1-10 under 12
MSI medium scale integration 100 10-100 12-99
LSI large scale integration 1,000 100-100,000 100-999
VLSI very large scale integration 10,000-100,000 from 100,000 from 1,000
ULSI ultra large scale integration 100,000-1,000,000 - -
SLSI super large scale integration 1,000,000-10,000,000 - -
ELSI extra large scale integration 10,000,000-100,000,000 - -
GLSI giant large scale integration > 100,000,000 - -

Individual evidence

  1. ^ Andrew S. Tanenbaum : Computer architecture. Structures - Concepts - Basics. 5th edition. ISBN 3-8273-7151-1 , p. 167.
  2. Texas Instruments : The TTL Data Book for Design Engineers. 2nd Edition. Texas Instruments Incorporated, Dallas 1976, pp. 3-7.