Digital ICs are basically categorized according to their complexity of circuit and also their logic gates. According to this, there are 5 standards levels of complexity in digital electronics. These all are given below:
Small Scale Integration(SSI):
In this circuit, less than 12 gate circuit can stay on a single chip. It is to be noted that flip-flop and logic gates are in this category.
Medium Scale Integration(LSI):
In this circuit, 12 to 99 logic gate circuit can stay on a single chip.Counter,Register,multiplexers,demultiplexers,decoder,encoder are in this category.
Large Scale Integration(LSI):
In this circuit, 100 to 9999 logic gates can stay on a single chip.
Small memories, microprocessors belong in this category.
Very Large Scale Integration(VLSI)
In this kind of circuit 10,000 to 99,999 logic gates stay per chip. Large memories, microprocessors belong to this category.
Ultra Large Scale Integration(ULSI):
This is a very complex circuit. Above 100,000 logic gates can stay on a single chip. Very large memories, microprocessors belong in this category.