“There is Plenty of Room at the Bottom“
A popular talk delivered by Richard Feynman to American Physical Society at California Institute of Technology in the year of 1959. This talk at that time could foresee the possibility of the revolution which has been brought by VLSI today.
The term VLSI stands for Very Large Scale Integration. This is the field which involves packing more and more logic devices into smaller and smaller areas. VLSI circuits are everywhere … your computer, your car, your brand new state-of-the-art digital camera, the cell- phones…
The history of VLSI started way before 60 years when Jack Kilby invented “Integrated Circuit” in 1958. Integrating more electronic components (mainly transistors) on a single semiconductor base is known as Integrated Circuit. The first integrated circuits contained only a few transistors. Early digital circuits containing tens of transistors provided a few logic gates. The IC era has passed through SSI, MSI, LSI and then VLSI. These different eras have been differentiated based on the number of transistors on a single IC.
Evolution of Integrated Circuit
- SSI – Small Scale Integration (Tens of transistors)
- MSI – Medium Scale Integration (Hundreds of transistors)
- LSI – Large Scale Integration – (Thousands of Transistors) – demanded automation of design process – CAD started evolving
- VLSI – Very Large Scale Integration – (Tens of Thousands of Transistors) – CAD Tools are inevitable
The increase in the number of transistors per chip has been predicted by co-founder of Intel, Gordon Moore as follows; and the prediction proved to be almost satisfied:
“The number of transistors per chip would grow exponentially (double every 18 months)”
Integration improves the design. Following are the design metrics can be achieved by VLSI design:
- Higher speed
- Lower power
- Physically smaller
- Integration reduces manufacturing cost
- Higher reliability
- More functionality
The advancement of VLSI, now a days has made SoC (System on Chip) possible. An SoC system typically consists of a collection of components/subsystems on a single chip that are appropriately interconnected to perform specified functions for users. Microcontrollers are the examples of SoC. The following can be a block diagram of modern SoC.
