Introduction to Digital IC Design B.Supmonchai June 13, 2005 Introduction to Digital IC Design Boonchuay Supmonchai June 6th, 2006 2102-545 Digital ICs

Outlines Historical Perspectives Progresses in Semiconductor Industry B.Supmonchai June 13, 2005 Outlines Historical Perspectives Progresses in Semiconductor Industry Digital Design Metrics 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Questions to be answered B.Supmonchai June 13, 2005 Questions to be answered What is driving the IC industry? Why is designing digital ICs today different than it was before? Will it change in future? 2102-545 Digital ICs Introduction 2102-545 Digital ICs

The First Computer The Babbage Difference Engine (1832) Mechanical B.Supmonchai June 13, 2005 The First Computer The Babbage Difference Engine (1832) Mechanical 25,000 parts Cost £17,470 2102-545 Digital ICs Introduction 2102-545 Digital ICs

The First Electronic Computer ENIAC (1946) 17,468 Vacuum Tubes 167 sq.m. 160 KW $500,000 and 18 months to build Unreliable 2102-545 Digital ICs Introduction

The Transistor Revolution First Transistor (1947) Bardeen, Brattain, Shockley at Bell Lab Point Contact Germanium & Gold 2102-545 Digital ICs Introduction

The First Integrated Circuit First IC (1947) Kilby at TI Assembled Solid State Oscillator (a transistor + components) Germanium 7/16 in. If he’d only gone to vacation… 2102-545 Digital ICs Introduction

The Monolithic ICs First Monolithic BJT IC (1961) Fairchild Flipf-lop with 4 BJTs and 2 resistors Commercial ECL 3-input Gate, Motorola 1966 2102-545 Digital ICs Introduction

Intel 4004- Microprocessor B.Supmonchai June 13, 2005 Intel 4004- Microprocessor 1971 10 micron 2300 transistors 800 KHz operation 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Intel Pentium IV - Microprocessor B.Supmonchai June 13, 2005 Intel Pentium IV - Microprocessor 2000 0.18 micron 42 million transistors 1.5 GHz operation 2102-545 Digital ICs Introduction 2102-545 Digital ICs

More Recently Ultra Large Scale Integration System On Chip B.Supmonchai June 13, 2005 More Recently Ultra Large Scale Integration System On Chip More than 30 million transistors in 2002 Chip complexity has increased 1000 folds since its inception thirty years ago. The term “Very Large Scale Integration” remains universal to denote any high-complexity chip. 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Outlines Historical Perspectives Progresses in Semiconductor Industry B.Supmonchai June 13, 2005 Outlines Historical Perspectives Progresses in Semiconductor Industry Digital Design Metrics 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Economics of Semiconductor Market B.Supmonchai June 13, 2005 Economics of Semiconductor Market One of the fastest growing sectors in the worldwide economy 50 100 150 200 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 Year Global Semiconductor Billings (Billions of US$) 1018 transistors manufactured in 2003 100 million for every human on the planet! 2102-545 Digital ICs Introduction 2102-545 Digital ICs

B.Supmonchai June 13, 2005 Moore’s Law In 1965, Gordon Moore of Bell Lab noted that the number of transistors on a chip doubled every 18 to 24 months So he made a bold prediction that “Semiconductor technology will double its effectiveness every 18 months” 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Moore’s Law in Microprocessors B.Supmonchai June 13, 2005 Moore’s Law in Microprocessors 0.001 0.01 0.1 1 10 100 1000 1970 1980 1990 2000 2010 Year Transistors (MT) 2X growth in 1.96 years! Pentium IV Pentium III Pentium II P6 Pentium® 486 386 286 8086 8085 8080 8008 4004 Transistors on Lead Microprocessors double every 2 years 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Die size grows by 14% to satisfy Moore’s Law B.Supmonchai June 13, 2005 Die Size Growth 100 Pentium IV Pentium II Pentium III Pentium ® P6 Die size (mm) 486 10 386 286 8080 8086 8085 ~7% growth per year 8008 4004 ~2X growth in 10 years 1 1970 1980 1990 2000 2010 Year Die size grows by 14% to satisfy Moore’s Law 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Lead Microprocessors frequency doubles every 2 years B.Supmonchai June 13, 2005 Frequency P6 Pentium ® 486 386 286 8086 8085 8080 8008 4004 0.1 1 10 100 1000 10000 1970 1980 1990 2000 2010 Year Frequency (Mhz) Pentium IV Pentium III Pentium II Doubles every 2 years Lead Microprocessors frequency doubles every 2 years 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Lead Microprocessors power continues to increase B.Supmonchai June 13, 2005 Power Dissipation 0.1 1 10 100 1971 1974 1978 1985 1992 2000 Year Power (Watts) P6 Pentium 486 286 8086 386 8085 8080 8008 4004 Lead Microprocessors power continues to increase 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Power will be a major problem B.Supmonchai June 13, 2005 Power will be a major problem 0.1 1 10 100 1000 10000 100000 1971 1974 1978 1985 1992 2000 2004 2008 Year Power (Watts) 18KW 5KW 1.5KW 500W Pentium® proc 286 486 8086 386 8085 8080 8008 4004 Power delivery and dissipation will be prohibitive 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Power density too high to keep junctions at low temp B.Supmonchai June 13, 2005 Power Density 1 10 100 1000 10000 1970 1980 1990 2000 2010 Year Power Density (W/cm2) Rocket Nozzle Nuclear Reactor Hot Plate 8086 4004 P6 8008 8085 386 Pentium® proc 286 486 8080 Power density too high to keep junctions at low temp 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Not Only Microprocessors - DRAM B.Supmonchai June 13, 2005 Not Only Microprocessors - DRAM 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Not Only Microprocessors - Cell Phone B.Supmonchai June 13, 2005 Not Only Microprocessors - Cell Phone Analog Baseband Digital Baseband (DSP + MCU) Power Management Small Signal RF RF Cell Phone Digital Cellular Market (Phones Shipped) 1996 1997 1998 1999 2000 Units 48M 86M 162M 260M 435M (data from Texas Instruments) 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Looking into the Future … B.Supmonchai June 13, 2005 Looking into the Future … More portable, wearable, and more powerful devices for ubiquitous and pervasive computing… 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Complexity outpaces Design Productivity! B.Supmonchai June 13, 2005 Productivity Trends Logic Tr./Chip Tr./Staff Month. x 21%/Yr. compound Productivity growth rate 58%/Yr. compounded Complexity growth rate Source: Sematech 2003 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2005 2007 2009 10,000 1,000 100 10 1 0.1 0.01 0.001 Logic Transistor per Chip (M) 100,000 (K) Trans./Staff - Mo. Productivity Complexity Courtesy, ITRS Roadmap Complexity outpaces Design Productivity! 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Impact of Technology Scaling B.Supmonchai June 13, 2005 Impact of Technology Scaling Technology shrinks by a factor of 0.7/generation With every generation can integrate 2x more functions per chip; chip cost does not increase significantly Cost of a function decreases by 2x But … How to design chips with more and more functions? Design engineering population does not double every two years… 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Design Productivity Crisis B.Supmonchai June 13, 2005 Design Productivity Crisis We urgently need more efficient design methods! Exploit automation in various levels of abstraction  Computer-Aided Design (CAD) Tools 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Outlines Historical Perspectives Progresses in Semiconductor Industry B.Supmonchai June 13, 2005 Outlines Historical Perspectives Progresses in Semiconductor Industry Digital Design Metrics 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Major Challenges in Digital Designs B.Supmonchai June 13, 2005 Major Challenges in Digital Designs  DSM  1/DSM “Microscopic Problems” • Ultra-high speed design Interconnect • Noise, Crosstalk • Reliability, Manufacturability • Power Dissipation • Clock distribution. Everything Looks a Little Different “Macroscopic Issues” • Time-to-Market • Millions of Gates • High-Level Abstractions • Reuse & IP: Portability • Predictability • etc. …and There’s a Lot of Them! ? 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Design in Deep Submicron B.Supmonchai June 13, 2005 Design in Deep Submicron Design in the deep submicron (DSM) era creates new challenges Devices become somewhat different Global clocking becomes more challenging Interconnect effects play a more significant role Power dissipation may be the limiting factor We must understand and be able to design digital ICs in advanced technologies (at or below 180 nm) 2102-545 Digital ICs Introduction 2102-545 Digital ICs

B.Supmonchai June 13, 2005 Design Metrics How to evaluate performance of a digital circuit (gate, block, …)? Cost (Yield) Reliability (Noise Immunity) Scalability (Fan-In, Fan-out) Speed (delay, operating frequency) Power dissipation Energy to perform a function 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Cost of Integrated Circuits B.Supmonchai June 13, 2005 Cost of Integrated Circuits NRE (non-recurrent engineering) costs design time and effort, mask generation one-time cost factor Recurrent costs silicon processing, packaging, test proportional to volume proportional to chip area 2102-545 Digital ICs Introduction 2102-545 Digital ICs

NRE Cost is increasing Introduction B.Supmonchai June 13, 2005 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Die Cost Single Die Wafer Going up to 12” (30cm) B.Supmonchai June 13, 2005 Die Cost From http://www.amd.com Going up to 12” (30cm) Single Die Wafer 2102-545 Digital ICs Introduction 2102-545 Digital ICs

B.Supmonchai June 13, 2005 Cost Per Transistor Fabrication capital cost per transistor (Moore’s law) 0.0000001 0.000001 0.00001 0.0001 0.001 0.01 0.1 1 1982 1985 1988 1991 1994 1997 2000 2003 2006 2009 2012 Cost (¢-per-transistor) Year 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Yield Introduction B.Supmonchai June 13, 2005 2102-545 Digital ICs

Defects
 is approximately 3 Introduction B.Supmonchai June 13, 2005 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Some Examples (in 1994) 2 0.90 $900 1.0 43 360 71% $4 3 0.80 $1200 81 B.Supmonchai June 13, 2005 Some Examples (in 1994) Chip Metal layers Line width Wafer cost Def./ cm2 Area mm2 Dies/wafer Yield Die cost 386DX 2 0.90 $900 1.0 43 360 71% $4 486 DX2 3 0.80 $1200 81 181 54% $12 Power PC 601 4 $1700 1.3 121 115 28% $53 HP PA 7100 $1300 196 66 27% $73 DEC Alpha 0.70 $1500 1.2 234 53 19% $149 Super Sparc 1.6 256 48 13% $272 Pentium 1.5 296 40 9% $417 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Reliability Noise in Digital Integrated Circuits Inductive coupling B.Supmonchai June 13, 2005 Reliability Noise in Digital Integrated Circuits i ( t ) Inductive coupling Capacitive coupling v ( t ) Power and ground noise V DD 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Voltage Transfer Characteristics B.Supmonchai June 13, 2005 Voltage Transfer Characteristics VOH = f(VOL) VOL = f(VOH) VM = f(VM) V(y) V f OH V(y)=V(x) Switching Threshold V M DC Operations V OL V V V(x) OL OH Nominal Voltage Levels 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Mapping between Analog and Digital B.Supmonchai June 13, 2005 Mapping between Analog and Digital V out V “ 1 ” OH Slope = -1 V OH V IH Undefined Region V Slope = -1 IL V “ ” V OL OL V V V IL IH in 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Definition of Noise Margins B.Supmonchai June 13, 2005 Definition of Noise Margins V IH IL "1" "0" OH OL NM H L Noise margin high Undefined Region Noise margin low Gate Output Gate Input 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Key Reliability Properties B.Supmonchai June 13, 2005 Key Reliability Properties Absolute noise margin values are deceptive. A floating node is more easily disturbed than a node driven by a low impedance (in terms of voltages) Noise Immunity is the more important metric The capability to suppress noise sources (Regenerative property) Key metric: Noise transfer functions, Output impedance of the driver, and Input impedance of the receiver. 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Regenerative Property B.Supmonchai June 13, 2005 Regenerative Property A chain of inverters v 1 2 3 4 5 6 Ability to recover a corrupted signal to a well-defined digital signal 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Regenerative Property I B.Supmonchai June 13, 2005 Regenerative Property I Regenerative Vout v0 v2 v1 v3 f(v) finv(v) Vin Non-Regenerative Vout v0 v2 v1 v3 f(v) finv(v) Vin 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Fan-in and Fan-out M N Fan-in M Fan-out N B.Supmonchai June 13, 2005 Fan-in and Fan-out Indirectly define scalability N Fan-out N Fan-in M M 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Delay Definitions tpHL : High-to-Low propagation delay B.Supmonchai June 13, 2005 Delay Definitions tpHL : High-to-Low propagation delay V out t f pHL pLH r in 90% 10% 50% tpLH : Low-to-High propagation delay tr : Rise Time tf : Fall Time 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Ring Oscillator T = 2 tp N B.Supmonchai June 13, 2005 Ring Oscillator An example of how to find delay of an inverter tp v 1 2 3 4 5 v 4 5 V t T = 2 tp N 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Delay Model A First-order RC Network t = RC tp = ln (2) t = 0.69 RC B.Supmonchai June 13, 2005 Delay Model A First-order RC Network v out in C R t = RC tp = ln (2) t = 0.69 RC An Important model – matches delay of inverter 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Power Dissipation Vsupply Instantaneous power: B.Supmonchai June 13, 2005 Power Dissipation i(t) Vsupply GND Instantaneous power: p(t) = v(t) i(t) = Vsupply i(t) Peak power: Ppeak = Vsupply ipeak Average power: 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Energy and Energy-Delay Product B.Supmonchai June 13, 2005 Energy and Energy-Delay Product Power-Delay Product (PDP) = E = Energy per operation = Pav  tp Energy-Delay Product (EDP) = Quality metric of gate = E  tp Energy is limited in certain situations such as in Cell Mobile phone, PC Notebooks, etc. 2102-545 Digital ICs Introduction 2102-545 Digital ICs

Energy Calculation Examples B.Supmonchai June 13, 2005 Energy Calculation Examples First-order RC Network v out in C R 2102-545 Digital ICs Introduction 2102-545 Digital ICs

B.Supmonchai June 13, 2005 Summary Digital integrated circuits have come a long way and still have quite some potential left for the coming decades Some interesting challenges ahead Getting a clear perspective on the challenges and potential solutions is the purpose of this course. Understanding the design metrics that govern digital design is crucial Cost, reliability, speed, power and energy dissipation. 2102-545 Digital ICs Introduction 2102-545 Digital ICs