VLSI & ECAD LAB Introduction

VLSI

    Since the invention of the first IC (Integrated Circuit), the ability to pack more and more transistors onto a single chip has doubled roughly every 18 months, in accordance with the Moore’s Law By mid eighties, the transistor count on a single chip had already exceeded 1000 and hence came the age of Very Large Scale Integration or VLSI.

Though many improvements have been made and the transistor count is still rising( NVDIA’s 280 Series GPU has almost 1.4billion transistors), further names of generations like ULSI are generally avoided.

It was during this time when TTL lost the battle to MOS family owing to the same problems that had pushed vacuum tubes into negligence, power dissipation and the limit it imposed on the number of gates that could be placed on a single die.

VLSI

   The second age of Integrated Circuits revolution started with the introduction of the first microprocessor, the 4004 by Intel in 1972 and the 8080 in 1974 Today many companies like Texas Instruments, Infineon, Cadence, Synopsys, Celox Networks, Cisco, Micron Tech, National Semiconductors, ST Microelectronics, Qualcomm, Lucent, Mentor Graphics, Analog Devices, Intel, Philips, Motorola and many other firms have been established and are dedicated to the various fields in "VLSI" like Programmable Logic Devices, Hardware Descriptive Languages, Design tools, Embedded Systems etc.

Where do we actually see VLSI Technology in action? Everywhere, in personal computers, cell phones, digital cameras and any electronic gadget.

VLSI DESIGN

   VLSI chiefly comprises of Front End Design and Back End design these days.

  While front end design includes digital design using HDL, design verification through simulation and other verification techniques, the design from gates and design for testability, Backend design comprises of CMOS library design and its characterization. It also covers the physical design and fault simulation.

VLSI is dominated by the CMOS technology Process technology is rapidly shrinking from 180nm-> 60nm-> 40nm->28nm-> 20nm->14nm

ASIC

• • •

A

pplication

S

pecific

I

ntegrated

C

ircuit is an integrated circuit (

IC

) customized for a particular use, rather than intended for general purpose use` Modern ASICs often include entire microprocessors, memory blocks including ROM, RAM, EEPROM, Flash and other large building blocks. Such an ASIC is often termed a SoC (

S

ystem-

O

n-

C

hip) Popular ASIC methodologies – – – Standard cell design (Semi-custom design) Full-custom design Cell libraries, IP-based design : soft macros, hard macros

VLSI(ASIC) DESIGN FLOW

FPGA

• • • • A

F

ield

P

rogrammable

G

ate

A

rray (

FPGA

) is an integrated circuit designed to be configured by a customer or a designer after manufacturing—hence "field programmable“ The FPGA configuration is generally specified using a hardware description language (HDL) FPGAs can be used to implement any logical function that an ASIC could perform. The ability to update the functionality after shipping, partial re-configuration of a portion of the design and the low non-recurring engineering costs relative to an ASIC design (notwithstanding the generally higher unit cost), offer advantages for many applications.

A recent trend has been to take the coarse-grained architectural approach a step further by combining the logic blocks and interconnects of traditional FPGAs with embedded microprocessors and related peripherals to form a complete "system on a programmable chip

FPGA

• • • FPGAs contain programmable logic components called "logic blocks", and a hierarchy of reconfigurable interconnects that allow the blocks to be "wired together"— somewhat like many (changeable) logic gates that can be inter-wired in (many) different configurations The main units of a FPGA are the Logic Blocks, Input/Output Blocks & the Programmable Interconnect Logic blocks can be configured to perform complex combinational functions, or merely simple logic gates like AND and XOR. In most FPGAs, the logic blocks also include memory elements, which may be simple flip-flops or more complete blocks of memory

FPGA

• Applications of FPGAs include digital signal processing, software-defined radio, aerospace and defense systems, ASIC prototyping, medical imaging, speech recognition, cryptography, bioinformatics, computer hardware emulation, radio astronomy, metal detection and a growing range of other areas.