CMOS Topic 7 -_design_methodology
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CMOS Topic 7 -_design_methodology CMOS Topic 7 -_design_methodology Document Transcript

  • faizah amir/jke/polisas 1 EE603 – CMOS INTEGRATED CIRCUIT DESIGN Faizah Amir IC DESIGN METHODOLOGY At the end of this session, you should be able to: 1. explain the IC design methodology. 2. explain full custom design methodology. 3. explain semi-custom design methodology. 4. explain Programmable Logic Devices (PLD).
  • faizah amir/jke/polisas 2 IC DESIGN METHODOLOGY DESIGN METHODOLOGY TREE DIAGRAM IC DESIGN METHODOLOGY STANDARD IC Standard IC : • Integrated circuits designed and fabricated for general purpose use. • Standard IC is available in the market at a very low cost. • Examples of standard ICs: 74 - SERIES TTL, 4000 - SERIES CMOS, OP-AMP, TIMER, INSTRUMENTATION AMPLIFIER, MEMORY, MICROCONTROLLER, etc.
  • faizah amir/jke/polisas 3 IC DESIGN METHODOLOGY EXAMPLES OF STANDARD IC 74-series TTL 4000 series CMOS Op-Amp Timer Memory Microcontroller IC DESIGN METHODOLOGY EXAMPLES OF STANDARD IC
  • faizah amir/jke/polisas 4 IC DESIGN METHODOLOGY ASICs • Progress in the fabrication of IC's has enabled the designer to create fast and powerful circuits in smaller and smaller devices. • This also means that we can pack a lot more of functionality into the same area. • The biggest application of this ability is found in the design of ASICs. IC DESIGN METHODOLOGY ASICs ASICs stands for : Application Specific Integrated Circuits • ASICs are IC's that are created for specific purposes - each device is created to do a particular job. • ASICs are produced for only one or a few customers or applications. • ASICs are devices made for a specific application such as a mobile phone.
  • faizah amir/jke/polisas 5 EXAMPLES OF ASICs IC DESIGN METHODOLOGY IC DESIGN METHODOLOGY EXAMPLES OF ASICs GRAPHIC MEDIA ACCELERATOR SMART CARD CHIPS
  • faizah amir/jke/polisas 6 IC DESIGN METHODOLOGY ASICs Advantages ASICs COMPARISON BETWEEN ASICs AND STANDARD IC ASICs STANDARD IC 1. Chip is designed and manufactured specifically to meet a particular function. 2. Each manufacturer produces a different chip design. 1. Integrated circuits can be used by any party or user. 2. Most manufacturers produce chips with similar function. IC DESIGN METHODOLOGY
  • faizah amir/jke/polisas 7 ADVANTAGES & DISADVANTAGES OF ASICs IC DESIGN METHODOLOGY ADVANTAGES DISADVANTAGES Ability to perform a function that cannot be done using standard IC. Improve the performance of a circuit. Reduce the volume, weight and power requirement of a circuit. Increase the reliability of a given system by integrating a large number of functions on a single chip / a small number of chips. High design security features. (Piracy prevention) High design and processing cost. Complex chip fabrication equipment is required. Advanced computer software is required in designing the layout. Not economical if market demand is low. IC DESIGN METHODOLOGY
  • faizah amir/jke/polisas 8 IC DESIGN METHODOLOGY FULL CUSTOM DESIGN All the circuits and mask layouts are completely designed for the requirements of a particular IC. A microprocessor is an example of a full- custom design IC—designers spend many hours squeezing the most out of every last square micron of microprocessor chip space by hand. IC DESIGN METHODOLOGY FULL CUSTOM DESIGN It allows designers to include analog circuits, optimized memory cells. Full-custom ICs are the most expensive to manufacture and to design and only economic at very high volumes (millions/year). The manufacturing lead time (the time it takes just to make an IC—not including design time) is typically eight to ten weeks for a full-custom IC.
  • faizah amir/jke/polisas 9 ADVANTAGES & DISADVANTAGES OF FULL CUSTOM DESIGN METHOD IC DESIGN METHODOLOGY Advantages Disadvantages 1. High component density per chip. 2. Chip is able to operate at high frequency. 3. Flexible design. 4. Small chip size. 1. High design and manufacturing cost. 2. Design is exposed to errors. 3. Time-consuming design. 4. Advanced computer software is required in design process. IC DESIGN METHODOLOGY SEMI CUSTOM DESIGN To make ASICs economic at lower volumes, the semi-custom concept was introduced where many applications share the same basic configuration of logic cells. It is only the final interconnect stage that is different to give the different chips.
  • faizah amir/jke/polisas 10 IC DESIGN METHODOLOGY SEMI CUSTOM DESIGN The mask layers are customized to fulfill the requirements of a particular IC. Often used for speedy design with less effort compared to full custom design. IC DESIGN METHODOLOGY SEMI CUSTOM DESIGN There are 3 types of semi custom design:- 1. Gate array 2. Standard Cell 3. Programmable Logic Device (PLD)
  • faizah amir/jke/polisas 11 IC DESIGN METHODOLOGY Mask set for full custom & semi custom IC DESIGN METHODOLOGY SEMI CUSTOM IC GATE ARRAYGATE ARRAYGATE ARRAYGATE ARRAY 1. Gate arrays are integrated circuits containing large numbers of digital gates or transistor cells, which can be interconnected in different ways to implement various logic functions. 2. Gate array consists of transistors, usually arranged in two pairs of PMOS and NMOS. 3. Wafers containing these gate arrays have been processed up to all steps except the metallization layers.
  • faizah amir/jke/polisas 12 4. Using computer-aided-design tools, only the metallization layer patterns are required to be generated from the circuit specification, and the fabrication time can be very short. 5. Gate arrays can have several metallization layers to facilitate interconnection. 6. ASIC vendors offer a selection of gate array cells, with a different total numbers of transistors on each cell, for example, gate arrays with 50k-, 75k-, and 100k-gates. IC DESIGN METHODOLOGY SEMI CUSTOM IC – gate array IC DESIGN METHODOLOGY SEMI CUSTOM IC GATE ARRAY FLOOR PLAN
  • faizah amir/jke/polisas 13 IC DESIGN METHODOLOGY SEMI CUSTOM IC – gate array Gate array IC DESIGN METHODOLOGY SEMI CUSTOM IC – gate array
  • faizah amir/jke/polisas 14 IC DESIGN METHODOLOGY SEMI CUSTOM IC – gate array IC DESIGN METHODOLOGY SEMI CUSTOM IC – gate array
  • faizah amir/jke/polisas 15 ADVANTAGES & DIS ADVANTAGES OFADVANTAGES & DIS ADVANTAGES OFADVANTAGES & DIS ADVANTAGES OFADVANTAGES & DIS ADVANTAGES OF GATE ARRAYGATE ARRAYGATE ARRAYGATE ARRAY ADVANTAGES DISADVANTAGES Cheaper process Speedy design Low power dissipation IC Advanced CAD software is required in design. Not all of the gates offered by the vendor are being used in the design. Optimum circuit performance cannot be achieved. IC DESIGN METHODOLOGY GATE ARRAY IC DESIGN METHODOLOGY SEMI CUSTOM IC STANDARD CELLSTANDARD CELLSTANDARD CELLSTANDARD CELL 1. Standard cell design involves the use of pre- designed standard cell @ library cell that has been and stored in database. 2. Standard cell @ library cell consists of simple circuit such as inverter or logic gates (AND, OR, XOR, XNOR, flip-flop), and complex circuit such as register, adder, ROM and RAM.
  • faizah amir/jke/polisas 16 IC DESIGN METHODOLOGY SEMI CUSTOM IC STANDARD CELLSTANDARD CELLSTANDARD CELLSTANDARD CELL 3. Design is carried out by simply using the pre- designed cells from the library and then connect the cells so that certain functions can be implemented. 4. To facilitate placement and routing, the standard cells are designed to have equal height but variable widths, so that the final IC layout will have a regular pattern with rows of cells and interconnect routing running between the rows. STANDARD CELL FLOOR PLANSTANDARD CELL FLOOR PLANSTANDARD CELL FLOOR PLANSTANDARD CELL FLOOR PLAN IC DESIGN METHODOLOGY SEMI CUSTOM IC I/O Pads LOGIC BLOCK BLOCK Standard Cell Routing Standard Cell Routing Standard Cell Routing Standard Cell Routing
  • faizah amir/jke/polisas 17 ADVANTAGES AND DISADVANTAGESADVANTAGES AND DISADVANTAGESADVANTAGES AND DISADVANTAGESADVANTAGES AND DISADVANTAGES OF STANDARD CELLOF STANDARD CELLOF STANDARD CELLOF STANDARD CELL ADVANTAGEADVANTAGEADVANTAGEADVANTAGE DISADVANTAGEDISADVANTAGEDISADVANTAGEDISADVANTAGE THE PERCENTAGE OF USING ALL GATES ARE VERY HIGH. PRODUCE HIGH PERFORMANCE CHIP. THE OPTIMUM CHIP SIZE CAN BE ACHIEVED. THE CHIP CAN BE GUARANTEED TO FUNCTION WELL FOR THE FIRST TIME IT IS DESIGNED . the standard cells MUST BE designed to have equal height, so that the final IC layout will have a regular pattern . HIGH DESIGN COST. design cannot be done if the required cell is not available in the library. IC DESIGN METHODOLOGY SEMI CUSTOM IC PROGRAMMABLE LOGIC DEVICEPROGRAMMABLE LOGIC DEVICEPROGRAMMABLE LOGIC DEVICEPROGRAMMABLE LOGIC DEVICE (PLD)(PLD)(PLD)(PLD) Programmable Logic Device (PLD) is an array of logic gates that can be programmed by the user which contains functions of a small number of logic circuits in a single chip. IC DESIGN METHODOLOGY DEFINITION
  • faizah amir/jke/polisas 18 PROGRAMMABLE LOGIC DEVICE (PLD) PROGRAMMABLE LOGIC DEVICE (PLD) GENERAL CHARACTERISTICS OF PLD IC 1. PLD does not require a common mask layout in design. 2. The design time is shorter. 3. It consists of a large block of internal connections that can be a programmed. 4. Programming can be done at different stages: i) at the earliest, it is programmed by the semiconductor vendor (standard cell, gate array). ii) by the designer prior to assembly or field deployment. iii) by the user in circuit.
  • faizah amir/jke/polisas 19 ADVANTAGES OF PLD COMPARED TO STANDARD IC & ASICs PROGRAMMABLE LOGIC DEVICE (PLD) 1. Reduced complexity of circuit boards • Lower power requirements • Less board space • Simpler testing procedures 2. Higher reliability 3. Design flexibility PLD DESIGN BLOCK DIAGRAM OF PLD LOGIC
  • faizah amir/jke/polisas 20 PLD DESIGN PLD DESIGN
  • faizah amir/jke/polisas 21 PLD DESIGN TYPES OF PLD PROGRAMMABLE LOGIC DEVICE (PLD) Programmable Logic Devices (PLD) CPLDSPLD FPGA •••• PROM •••• PAL •••• PLA
  • faizah amir/jke/polisas 22 TYPES OF PLD • SPLD – SIMPLE PROGRAMMABLE LOGIC DEVICE • PROM – PROGRAMMABLE READ ONLY MEMORY • PAL – PROGRAMMABLE ARRAY LOGIC • PLA – PROGRAMMABLE LOGIC ARRAY • FPGA – FIELD PROGRAMMABLE GATE ARRAY • CPLD – COMPLEX PROGRAMMABLE LOGIC DEVICES PROGRAMMABLE LOGIC DEVICE (PLD) PLD DESIGN DIFFERENCES BETWEEN PROM, PAL, PLA Summaries of differences between Programmable ROM (PROM), Programmable Array Logic (PAL), and Programmable Array Logic (PLA) PROM PAL PLA AND array (hardwired) AND array (programmable) AND array (programmable) OR array (programmable) OR array (hardwired) OR array (programmable)
  • faizah amir/jke/polisas 23 PLD DESIGN PROM ARCHITECTURE = fixed by manufacturer = programmed by user AND plane = Fixed OR plane = Programmable O0 = I0 I1 I2 I3 + I0 I1 I2 I3 + I0 I1 I2 _ _ _ _ _ _ O1 = I0 I1 I2 I3 __ O3 = I0 I1 I2 I3 + I0 I1 I2 _ __ __ O0 O1 O2 O3 I0 I1 I2 I3 PLD DESIGN PAL ARCHITECTURE • AND plane = programmable • OR plane = fixed O0 O1 O2 O3 I0 I1 I2 I3 O0 = I0 I1 I2 I3 + I0 I1 I2 I3 + I0 I1 I2
  • faizah amir/jke/polisas 24 PLD DESIGN PLA ARCHITECTURE X1 X2 X3 f1 f2 f3 • Both AND & OR plane can be programmed f1 = X1 X2 + X1 X3 + X1 X2 X3 _ _ _ • Boolean Expression • Schematic Capture • Truth Table PLD DESIGN PLD PROGRAMMING METHODS
  • faizah amir/jke/polisas 25 PLD DESIGN Three methods of programming PLD: i) Schematic Capture. ii) Boolean Expression using Hardware Description Language (HDL). iii) Truth Table / State Diagram. PLD PROGRAMMING METHODS PLD PROGRAMMING METHOD DESIGN LANGUAGE Types of high level language used in PLD programming :- •HDL (Hardware Description Language) VHDL (Very High Speed IC HDL) Verilog •CUPL (Universal Compiler for Programmable Logic) •PALASM (PAL Assembler) •ABEL (Advanced Boolean Expression Language)
  • faizah amir/jke/polisas 26 3 methods of memory storing in PLD: 1) FAMOS - Floating Gate Avalanche Injection Metal Oxide Semiconductor 2) Fuse 3) Anti- Fuse PLD MEMORY STORING METHOD 1. FAMOS TRANSISTOR FAMOS - Floating Gate Avalanche Injection Metal Oxide Semiconductor FAMOS transistor is the basic building block used to construct the memory cells in non-volatile data storage such as flash, EPROM and EEPROM memory. Floating gate in FAMOS will trap and discharge charges. P n+ n+ Gate Floating Gate SiO2 Gate Physical Structure Symb ol PLD MEMORY STORING METHOD
  • faizah amir/jke/polisas 27 FAMOS TRANSISTOR The data stored in the memory is non-volatile: data is still exist although the supply is removed. P n+ n+ + + + + + + + + Vg =0 PLD MEMORY STORING METHOD TRANSISTOR FAMOS +25V P subs n+ n+ +16V Depletion region n channel FAMOS in ON state: High Voltage is supplied between Source and Drain ~ 16-20V. High voltage is also supplied at the gate (~25V). n channel exists at the wafer surface due to high voltage at the gate. The channel is tapered at the drain due to high voltage between source-drain. Source-drain voltage will accelerate electrons (known as hot electrons) through the existing channel. Since the SiO2 layer is very thin, this will cause avalanche breakdown of the gate insulating layer allowing electrons to travel through this SiO2 layer to the floating gate, giving the floating gate electrode an electrical charge. PLD MEMORY STORING METHOD
  • faizah amir/jke/polisas 28 TRANSISTOR FAMOS PLD MEMORY STORING METHOD FAMOS in OFF state: When the floating gate is charged, it modifies the threshold voltage of the control gate, inhibiting its operation. Thus, it can be set to lock the transistor in its off state, distinguishing it from similar transistor which have not bee charged (programmed). +25V P subs n+ n+ +16V Depletion region n channel The property of FAMOS transistor can be used to provide read-only memory (ROM) function. The floating gate can be restored to its uncharged state by exposure to strong ultraviolet light which causes the charge to leak away. Arrays of floating gate transistors in IC are used to provide erasable programmable read-only memory (EPROM). In practice, a programmed EPROM retains its data for about ten to twenty years and can be read an unlimited number of times. Fuse is a two-terminal programmable element that is normally a low resistive element and is programmed or "blown" resulting in an open or high impedance. 2. FUSE PLD MEMORY STORING METHOD
  • faizah amir/jke/polisas 29 3. ANTI-FUSE • Anti-fuse is a two-terminal element that is normally a high resistive element and is programmed to a low impedance. PLD MEMORY STORING METHOD DIFFERENCE BETWEEN FUSE AND ANTI-FUSE Fuse links Anti-fuse links PLD MEMORY STORING METHOD
  • faizah amir/jke/polisas 30 LARGE SCALE PLD CPLD & FPGA CPLD CPLDs CPLDs evolved from PALPLAs - as chip densities increased, it was natural for the PLD manufacturers to evolve their products into larger parts (several tens of thousands of gates). Larger sizes of CPLDs allow either more logic equations or more complicated designs to be realised. LARGE SCALE PLD
  • faizah amir/jke/polisas 31 CPLD LARGE SCALE PLD CPLDs - Applications GPS Navigation Systems - Hard disk controller - GPIO interface - Timing configuration - LCD Timing Control - GPIO Expansion - Power Management - Level Shifting PDA
  • faizah amir/jke/polisas 32 CPLDs - Applications - Keypad scanner - Logic consolidation - Controller and interface conversion - Interface expansion - Simple glue logic PrinterGSM Phone CPLDs - Applications P1200 portable handsets (Shenzhen Huayu Communications Technology Company, China ) • Altera MAX II CPLD • Interfaces with: - Radio Frequency Identification (RFID) reader - Infrared Data (IRDA) sensor - Bluetooth interface
  • faizah amir/jke/polisas 33 CPLDs - Applications Robot controller CD/audio controller FPGA This device is similar to the gate array, with the device shipped to the user with general-purpose metallization pre-fabricated, often with variable length segments or routing tracks. The device is programmed by turning on switches which make connections between circuit nodes and the metal routing tracks. The connection may be made by a transistor switch (which are controlled by a programmable memory element) or by an anti-fuse. LARGE SCALE PLD
  • faizah amir/jke/polisas 34 FPGA LARGE SCALE PLD FPGA LARGE SCALE PLD
  • faizah amir/jke/polisas 35 LARGE SCALE PLD COMPARISON BETWEEN CPLD & FPGA CPLD FPGA Cheaper More expansive Faster operation Slower Contain less gates Contain more gates Use for interfacing purpose Use for heavy computation purpose Include built-in flash memory Need external memory Comparison between full custom and semi custom design Full Custom Semi custom i. Small chip size. i. Large chip size. ii. Large number of mask. ii. Small number of mask. iii. Time-consuming design. iii. Faster design time. iv. High circuit performance. iv. Low circuit performance. IC DESIGN METHODOLOGY
  • faizah amir/jke/polisas 36 DESIGN METHODOLOGY DIFFERENCES Design method Design cost Chip size Operation speed Power dissipation No. of mask Design time Full custom The most expensive The smallest Highest speed 5x Smaller Numerous Time- consuming Standard cell Average Small High-speed 3x smaller Many Average Gate array Cheaper Large Slow 2x Smaller 1@2 piece Fast PLD The Cheapest Largest Slowest 1x Smaller None The fastest IC DESIGN METHODOLOGY DESIGN METHODOLOGY CRITERIA Criteria of selecting design methodology : • Operation speed • Components density • Power dissipation • Interface compatibility with other circuit • Design and fabrication cost • Integrated circuit testability IC DESIGN METHODOLOGY
  • faizah amir/jke/polisas 37 1. Explain briefly these IC design methodologies: i. Full custom ii. Semi custom (10 marks) 2. State 2 differences between ASICs chip with general chip / standard IC. (4 marks) 3. State 2 advantages and 2 disadvantages of ASICs . (4 marks) 4. i. What is the meaning of gate array? ii. Sketch and label the floor plan of gate array. (6 marks) 5. State 2 advantages of standard cell. (2 marks) Example of final exam questions IC DESIGN METHODOLOGY THE END