Introduction

What is VLSI???

VLSI stands for Very Large Scale Integration. This is the field which involves integration or packing of more and more logic device in a small and smaller area.

History of Integrated Circuits.

1. Bardeen, Brattain & Schockly invented transistor in 1948 (23rd dec. 1946).
2. Schockly invented FET (Field Effect Transistors) in 1952. (FET invented before BJT but nobody accepted)
3. Jack kilby invented IC in 1958 he designed first Flip flop by using two transistor.
4. In 1965 Gordon Moore observes that the transistor count becomes double for every 18 or 24 months. This observation called as Moore's law.

Integrated Circuits

Integrated Circuits consists of active & passive device and also interconnections fabricated on a single crystal of silicon or germanium chip.

IC fabrication is batch process i.e. more no. of circuits can be fabricated in an one chip.

Advantages of  ICs:

• Minimization, so increase equipment density.
• Cost reduction due to batch processing.
• Increase reliability due to elimination of soldering joints.

Levels of Integration

SSI: Such as 7404 inverter have upto 10 gates/chip. Ex: Logic gates, Flip flops.

MSI: Such as counter 74161,64,63, have upto 1000 Gates/chip. Ex: Counter, MUX, Adders.

LSI: Such as simple 8-bit microprocessor have upto 10000 gates/chip. Ex: ROM, RAM.

VLSI: Greater than 10000  gates/chip or 1 million transistors/chip. Ex: 16-bit, 32-bit, 64-bit microprocessor.