1 overview of vlsi

Digital VLSI Circuits

E0-284

Bharadwaj Amrutur amrutur@ece.iisc.ernet.in

http://chips.ece.iisc.ernet.in Associate Professor

ECE Department IISc Bangalore

Class Timings: Tuesday/Thursday 11:15am to 12:30pm Lab Timings: Tuesday/Thursday 2pm to 5.30pm CEDT Multimedia and Microelectronics Labs http://chips.ece.iisc.ernet.in/ and click on Courses Grading: 30% Midterms quizzes: once end of Aug,Sept,Oct

40% Mini-Project (due middle of Nov), 30% Final (first week of December) Text: CMOS VLSI Design. 4th Edition. Weste/Harris http://cmosvlsi.com

Logistics Class Timings: M-W-F 2:00pm to 2:50pm in ECE 1.08 Lab Timings: Anytime you can get access to a machine with

opensource tools: LTI-SPICE. You can also use Eldo if you want Grading: Periodic quizzes, mid-term, mini-project, final

Class website: http://chips.ece.iisc.ernet.in (courses link) Text: CMOS VLSI Design. 4th Edition. Weste/Harris

Why should we care about Digital IC Design?

Digital ICs in FORBES’ top 30 innovations in 30 years

1. Internet, broadband, www (browser and html) 2. PC/laptop computers 3. Mobile phones 4. E-mail 5. DNA testing and sequencing/human genome mapping 6. Magnetic Resonance Imaging (MRI) 7. Microprocessors 8. Fiber optics 9. Office software (spreadsheets, word processors) 10. Non-invasive laser/robotic surgery (laparoscopy) 11. Open-source software and services (e.g., Linux, Wikipedia) 12. Light-emitting diodes 13. Liquid crystal display (LCD) 14. GPS systems 15. Online shopping/e-commerce/auctions (e.g., eBay)

http://www.forbes.com/2009/02/19/innovation-internet-health-entrepreneurs-technology_wharton.html

Digital ICs in FORBES’ top 30 innovations in 30 years

16. Media file compression (jpeg, mpeg, mp3) 17. Microfinance 18. Photovoltaic solar energy 19. Large- scale wind turbines 20. Social networking via the Internet 21. Graphic user interface (GUI) 22. Digital photography/videography 23. RFID and applications (e.g., EZ Pass) 24. Genetically modified plants 25. Bio fuels 26. Bar codes and scanners 27. ATMs 28. Stents 29. SRAM flash memory 30. Anti-retroviral treatment for AIDS

http://www.forbes.com/2009/02/19/innovation-internet-health-entrepreneurs-technology_wharton.html

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The physical view

What is an IC (Integrated Circuit)?

Jack S. Kilby: Nobel Prize in Physics 2000

Physical View: IC is built up in layers

Silicon base

Xtor gate

Metal 1

Metal 2

Metal 3

High-k Gate oxide

ILD: Inter layer dielectric

ILD: Inter layer dielectric

ILD: Inter layer dielectric

Passivation

Transistor (Xtor)

Other active devices

Patterning of each layer and inter layer connection

Silicon base

Xtor gate

Metal 1

Metal 2

Metal 3

High-k Gate oxide

ILD: Inter layer dielectric

ILD: Inter layer dielectric

ILD: Inter layer dielectric

Passivation v

v vv

Via

Metal pad to connect to outside world

Geometric patterns for each layer

Active devices: Transistors, Diodes, ….

Silicon Substrate (P)

High-k Gate oxide

NMOS PMOS

NWELL (n-doping)

Source (s) Drain (d)

Gate (g)

n+ n+ p+ p+

Diode

Can also make BJTs, standalone diodes, …..

The functional view

Functional View: a typical Mixed Signal IC

DIGITAL IP

ANALOG IP

Some lingo •  IP : Intellectual Property •  SoC : System on Chip •  NoC : Network on Chip •  EDA: Electronic Design Automation •  ASIC: Application Specific Integrated

Circuit •  HDL : Hardware Description Language •  Full Custom/Semi Custom/ASIC Flow •  Physical Design

Digital Design Tasks Functional description

HDL description

Assemble chip

Std. Cells RAMs IO

cells Macros

Digital Design Tasks

Functional description

HDL description

Assemble chip

Std. Cells RAMs IO

cells Macros

Chip Development

Component Development

Digital Design Tasks

Functional description

HDL description

Assemble chip

Std. Cells RAMs IO

cells Macros

Manual (mostly)

Automated (mostly)

Design

Manual (mostly)

Digital Design Tasks

Functional description

HDL description

Assemble chip

Std. Cells RAMs IO

cells Macros

Manual (mostly)

Automated (mostly)

Design

Manual (mostly)

Verification

Manual (mostly)

Automated (mostly)

Manual (mostly)

Design Goals Meet functional Specs Minimize Power Minimize Area Maximize speed (or meet speed target) Meet reliability requirements Minimize verification cost Minimize test cost Minimize Packaging cost Minimize system integration cost

Two basic aspects to design

•  Functional/Logical Design •  Physical design

•  Where the logical design meets physics •  Deal with area, power, speed, reliability, integrity

Course Goals •  Largely focused on physical design aspects

•  Transistors, wires, deep submicron issues •  delay, power and energy for digital circuits •  digital circuit design concepts, basic digital cells,

sequencing elements •  Clocking, clock distribution techniques, timing

constraints •  Memory structures •  Low power techniques like power gating, multi-

threshold, sizing, parallelism, minimum energy operation

•  IO and packaging