Frequently asked questions about ASICs
        
  What is an ASIC ?
   

Application Specific Integrated Circuit. Ten years back the electronic designers used several standard chips together on a board to create a special function. This is too big, too slow, too easy to copy or too power-consuming for many applications today. The solution is to put the whole design into the same chip, an ASIC.

A modern ASIC is big; I have worked with 100 Mgate ASIC's. For comparison: A Z80 processor will need about 0.02 Mgate. 

An ASIC will typically take five to ten man-years to design.

   
  What does it look like ?
    The buttons below show an ASIC I've designed. The finest details of the asic is 0.35 m (i.e. invisible even on the close-ups). 
    Click to enlarge. Click to enlarge.
Click pictures to see close-ups.
    The naked chip is about 12 x 12 mm. The lighter areas are memories.   The chip mounted into a package.  Note the thin silver wires connecting  the chip to the gold pins.
   
 

Where do you find ASIC's ?

   

Almost in all electronic equipment: PC's, Mobile phones, Answer machines, Watches, CD players, Pacemakers, Telecom switches, Synthesizers, Toys etc

   
  What is hardware description languages ?
   

The traditional way to describe a design is to draw a schematic diagram. Today when a design can consist of up to a 10.000.000 units (gates, registers) this is considered too slow, too hard to overview, too hard to verify etc.

Using a hardware description languages (such as VHDL or Verilog) it is possible to describe a behavior of a circuit. This CODE can then be simulated (verified) and synthesized (turned into a schematic diagram).

   
 

Why do you use workstations/UNIX ?

   
  • It's stable. Our simulations/syntheses can take several hours to run. A crash can then cost a days work.
  • I can do a remote-login on another computer when I need more processing power.
  • Unix contains a lot of filtering, processing and editing possibilities. Trivial example: It takes only one command line to find all lines containing 'Error' in a 20 Mbyte file and then sort the result based on the content of the 3'rd column.
  • UNIX Tools follows another tradition than PC tools; It doesn't 'hide' setup files all over the disk, and almost all files are readable text. This makes it possible to tweak/debug/control the behavior of a tool.
  • Licenses for the tools we use costs $10 000 and up. So the computer cost is usually not an issue.
  • But the trend is clear: more and more EDA tools are available for PC. Maybe Linux on PC will be the dominating platform?
   
 

What tools do you use ?

    For design entry: Summits VisualHDL,
Mentor Graphics Renoir
       
    For synthesis: Synopsys Design_compiler,
Synopsys Fpga_express,
Synplicitys Synplify
       
    For simulation:   Mentor Graphics Modelsim
       
    ATPG generation: Synopsys Test_compiler
       
    Static Timing Analysis: Mentor Graphics QuickPath,
Quad design Motive.
     
    + a zillion smaller tools which usually are vendor-dependant.
   
 

What vendors have you worked with ?

    Texas Instruments, TGB1000 0.7, 5V, BiCMOS Gate array
     Motorola, M5C 0.5, 3.3V, CMOS Gate array
    VLSI Technology, VSC883 0.35, 2.5V, CMOS Standard cell
    Matra MHS, MG2 0.5, 5V, CMOS, Embedded gate array
    LSI technology, G12-d 0.18, 1.8V, CMOS, Standard cell
    TSMC, 013G 0.13, 1.2V, CMOS, Standard cell
   
 

What is deep sub-micron technology ?

   

The most important parameter for chip design is the size of the smallest details on the chip. 'Deep sub-micron' means much smaller than micro-meter (1 m = 0.001 mm or 0.00004 inch). Today we are looking towards 0.13 technologies. Using a smaller technology will get you:

  • More gates into a chip.
  • Faster clocking possible.
  • Lower power dissipation.
  • Better layout/synthesis tools necessary, since interconnect delay within the chip may be in the same order as the delay through the gates.
  • Higher manufacture cost.
  • Higher test cost, since more need for at-speed test and because Iddq tests are not as effective.
   
 

What are the most important factors when developing new products ?

    - Time to market The most important factor !
    - Power consumption Especially for battery operated equipment.
    - Manufacture cost E.g. toys.
    - Product size E.g. mobile phones.
    - Testability Check that the chip is correctly manufactured.
    - Verify-able Check that the chip is correctly designed.
    - Reusable design Engineering cost is often the highest cost.
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