What is the difference between ASIC and FPGA?.

Guest
Hello, I have two questions about Electronic circuit board design.
These are the questions:

1st question:
What is the main difference between FPGA and ASIC, recently I went to
some exhibition, there I heard from somebody, he says "we are designing
a prototype handset based on FPGA, which was used between DSP chip and
main processor, later on we will go wityh ASIC", I didn't understand
quite well, what was the main difference, also whereever FPGA was used,
can that be replaced by ASIC?.

2nd question:
What are the main stepps involved in circuit board design?. Suppose if
I want some board to be designed, what are the steps I have to do (like
a fabless design), how can I contact the fab to get my prottype board
as well as production baord?.

Thanks in advance, appreciated.
 
Tam/WB2TT wrote:

An FPGA is a Field Programmable Logic array.
Click to expand...
Minor correction: An FPGA is a Field Programmable Gate Array.
^ ^^^^
 
In article <10ujide6a3m28aa@corp.supernews.com>,
Guy Macon <_see.web.page_@_www.guymacon.com_> wrote:
Tam/WB2TT wrote:

An FPGA is a Field Programmable Logic array.

Minor correction: An FPGA is a Field Programmable Gate Array.
Click to expand...
If you'd done it in an FPGA, no-one would even know you made the mistake.
As it is you did it in an ASIC so you had to turn the design.

--
--
kensmith@rahul.net forging knowledge
 
On Sun, 16 Jan 2005 02:11:28 +0000, Ken Smith wrote:

In article <10ujide6a3m28aa@corp.supernews.com>,
Guy Macon <_see.web.page_@_www.guymacon.com_> wrote:

Tam/WB2TT wrote:

An FPGA is a Field Programmable Logic array.

Minor correction: An FPGA is a Field Programmable Gate Array.

If you'd done it in an FPGA, no-one would even know you made the mistake.
Click to expand...
If I'd done it in an FPGA, I still couldn't stand up. My '70 Gremlin was
small enough!

As it is you did it in an ASIC so you had to turn the design.
Click to expand...
They would have know it long before, when you wrote the check for the
masks, the counters of beans would have noticed.

--
Keith
 
tvnaidu@yahoo.com wrote:
What is the main difference between FPGA and ASIC, recently I went to
some exhibition, there I heard from somebody, he says "we are
designing a prototype handset based on FPGA, which was used between
DSP chip and main processor, later on we will go wityh ASIC", I
didn't understand quite well, what was the main difference, also
whereever FPGA was used, can that be replaced by ASIC?.
Click to expand...
Development / debugging:
An FPGA can be re-programmed again and again, until you get it right.
An ASIC is hard-wired with a mask - you can't change it once it's
fabricated!

Power:
An FPGA consumes more power than an ASIC.

Cost per unit:
ASICs are only made in large quantities - the total investment is large -
but the unit cost is small.
FPGAs can be used for one-offs, but would not be competitive in large
voilumes.
 
Ken Smith wrote:
In article <1105837359.911078.236150@z14g2000cwz.googlegroups.com>,
tvnaidu@yahoo.com> wrote:

Hello, I have two questions about Electronic circuit board design.
These are the questions:

1st question:
What is the main difference between FPGA and ASIC, recently I went to


Field Programable Gate Array: a bunch of logic cells that you can program
to do lots of different things. One of these things would may be the
thing you want done.

Application Specific Integrated Circuit: a chip designed to do a certain
job or a small group of jobs. If you want to do something else get a
different chip.



some exhibition, there I heard from somebody, he says "we are designing
a prototype handset based on FPGA, which was used between DSP chip and
main processor, later on we will go wityh ASIC", I didn't understand
quite well, what was the main difference, also whereever FPGA was used,
can that be replaced by ASIC?.


Basically it like this:

You can make the prototype with very costly general purpose FPGAs, some
DSPs, and have a cable running off to a big battery. This version costs a
billion dollars each. Our target cost is 3 dollars so we will have to
spend 10 Million on making a custom chip and sell about 4 million units to
make it pay.


2nd question:
What are the main stepps involved in circuit board design?.


1) Decide what the bourd should do.
2) Make a schematic that does that.
3) Decide the mounting issues.
4) Select the component packages.
5) Buy board layout software if you intend to do it yourself
6) Start placing the parts
7) Discover that they won't fit and loop back to 3
8) Finish placing
9) Start running the traces
10) Discover that you can't route as placed and loop back to 8
11) Finish routing
11) Check the proposed layout
12) Rip out large sections and loop back to 8
13) Check the improved version
14) Check it again
15) Make Gerber plots and an NC drill file
16) Check the Gerbers and drill file
17) Compose a README.TXT
18) Zip together the Gerber, NC drill and README.TXT
19) Get bids on making the board
20) Select a vendor and send off the files
21) Get a phone call from the vendor pointing out an error
22) Loop back to 11 and increase the ring on the vias etc
23) Get the boards from the FAB house.
24) Gather the parts needed
25) Discover that you can't get the MOSFET in a DPAK loop back to 4
26) Stuff the board
27) Apply power
28) Scrape the burning parts off your face
29) Replace the burned parts
30) Apply the right power the right way around this time
31) Begin debugging the board
32) Discover the errors that are not just part values
33) Loop back to 1
34) Prepair BOMs etc for the production build.
35) Fight off the accounting guy who wants to lower cost.
36) Make the pre-pre-production units
37) Correct the BOM and assembly drawings
38) Start testing the pre-pre-production units
39) Build the pre-production units
40) Do major testing
41) Discover that the specifications from marketing have changed
42) Loop back to 1
Click to expand...

This is good! We should put this in a F.A.Q. ;)




-- "Welcome to the new millennium, where ingenuity is dead and
SpongeBob Squarepants rules the world..." MCJ 200406
 
kensmith@green.rahul.net (Ken Smith) wrote in
news:cscid6$76e$3@blue.rahul.net:

2nd question:
What are the main stepps involved in circuit board design?.

1) Decide what the bourd should do.
2) Make a schematic that does that.
3) Decide the mounting issues.
4) Select the component packages.
5) Buy board layout software if you intend to do it yourself
6) Start placing the parts
7) Discover that they won't fit and loop back to 3
8) Finish placing
9) Start running the traces
10) Discover that you can't route as placed and loop back to 8
11) Finish routing
11) Check the proposed layout
12) Rip out large sections and loop back to 8
13) Check the improved version
14) Check it again
15) Make Gerber plots and an NC drill file
16) Check the Gerbers and drill file
17) Compose a README.TXT
18) Zip together the Gerber, NC drill and README.TXT
19) Get bids on making the board
20) Select a vendor and send off the files
21) Get a phone call from the vendor pointing out an error
22) Loop back to 11 and increase the ring on the vias etc
23) Get the boards from the FAB house.
24) Gather the parts needed
25) Discover that you can't get the MOSFET in a DPAK loop back to 4
26) Stuff the board
27) Apply power
28) Scrape the burning parts off your face
29) Replace the burned parts
30) Apply the right power the right way around this time
31) Begin debugging the board
32) Discover the errors that are not just part values
33) Loop back to 1
34) Prepair BOMs etc for the production build.
35) Fight off the accounting guy who wants to lower cost.
36) Make the pre-pre-production units
37) Correct the BOM and assembly drawings
38) Start testing the pre-pre-production units
39) Build the pre-production units
40) Do major testing
41) Discover that the specifications from marketing have changed
42) Loop back to 1
Click to expand...
Here's a good tutorial about designing PCBs (minus all the real-world
details given in the list above):

http://www.pcb123.com/tutorials/PDF%20Documents/PCBDesignTutorialRevA.pdf



--
----------------------------------------------------------------
Dave Van den Bout
XESS Corp.
PO Box 33091
Raleigh NC 27636
Phn: (919) 363-4695
Fax: (801) 749-6501
devb@xess.com
http://www.xess.com
 
On Sun, 16 Jan 2005 11:51:37 -0500, Mark Jones wrote:

<snipped THREE PAGES of THRICE-QUOTED crap>

This is good! We should put this in a F.A.Q. ;)
Click to expand...
Great Idea!

Where's the FAQ?

Thanks,
Rich
 
<tvnaidu@yahoo.com> wrote in message
news:1105837359.911078.236150@z14g2000cwz.googlegroups.com...
Hello, I have two questions about Electronic circuit board design.
These are the questions:

1st question:
What is the main difference between FPGA and ASIC, recently I went to
some exhibition, there I heard from somebody, he says "we are designing
a prototype handset based on FPGA, which was used between DSP chip and
main processor, later on we will go wityh ASIC", I didn't understand
quite well, what was the main difference, also whereever FPGA was used,
can that be replaced by ASIC?.

2nd question:
What are the main stepps involved in circuit board design?. Suppose if
I want some board to be designed, what are the steps I have to do (like
a fabless design), how can I contact the fab to get my prottype board
as well as production baord?.

Thanks in advance, appreciated.

An FPGA is a Field Programmable Logic array. As the name implies, it can be
Click to expand...
programmed to be anything within its capability. ASIC stands for Application
Specific IC. In his context, he means a custom IC. So, the FPGA is a
prototype for the final version. You don't make one ASIC, you make
tens/hundreds of thousands.

Tam
 
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