Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

What is the difference in the speed of FPGAs like Xilinx and Altera?

Status
Not open for further replies.

pravi

Junior Member level 3
Joined
Sep 10, 2005
Messages
31
Helped
3
Reputation
6
Reaction score
1
Trophy points
1,288
Location
hassan
Activity points
1,530
What is the difference in the speed grade of FPGA's like xilinx and altera.

Xilinx has V-5 devices with -1,-2,-3
and Altera also have -4.-5,-6.

Is it some thing relates with the propogatin delay or how does this affect timing
 

echo47

Advanced Member level 5
Joined
Apr 7, 2002
Messages
3,942
Helped
637
Reputation
1,272
Reaction score
88
Trophy points
1,328
Location
USA
Activity points
33,183
Speed grade

FPGA speed grade numbers usually don't mean anything like nanoseconds or megahertz.
They are simply code numbers that you refer to in the data sheet.
 

pravi

Junior Member level 3
Joined
Sep 10, 2005
Messages
31
Helped
3
Reputation
6
Reaction score
1
Trophy points
1,288
Location
hassan
Activity points
1,530
Re: Speed grade

No , You are wrong. They are not just mere code numbers printed on the FPGA.

You know if you buy -1 device for $5 then -2 will be around $8 . Just check with your FPGA vendor
 

echo47

Advanced Member level 5
Joined
Apr 7, 2002
Messages
3,942
Helped
637
Reputation
1,272
Reaction score
88
Trophy points
1,328
Location
USA
Activity points
33,183
Speed grade

No, you misunderstood my correct but unclear answer. I'll try to clarify.

In the old days, the speed grade of many PLD or GAL devices would directly tell you the performance. For example, -4 -5 or -7 would mean 4ns 5ns or 7ns.

Modern FPGAs speed grades usually don't have any intrinsic meaning like that. Now they are simply code numbers that you must look up in the AC Specifications section of the data sheet. The data sheet gives columns of timing parameters for each speed grade. Some FPGAs have hundreds of different parameter values for each speed grade.
 

pravi

Junior Member level 3
Joined
Sep 10, 2005
Messages
31
Helped
3
Reputation
6
Reaction score
1
Trophy points
1,288
Location
hassan
Activity points
1,530
Re: Speed grade

Sorry, Can you send me the data sheet for the same for better understanding
 

echo47

Advanced Member level 5
Joined
Apr 7, 2002
Messages
3,942
Helped
637
Reputation
1,272
Reaction score
88
Trophy points
1,328
Location
USA
Activity points
33,183
Speed grade

Here's the Virtex-5 info:
"Virtex-5 Data Sheet: DC and Switching Characteristics"
http://direct.xilinx.com/bvdocs/publications/ds202.pdf

You didn't mention a particular Al.tera device, so here's a guess:
"Volume 2 - Stratix III Device Datasheet"
http://www.altera.com/literature/hb/stx3/stx3_siii5v2.pdf

Those data sheets contain a lot of terms and abbreviations that won't make much sense unless you read additional user guides and manuals. If you'd like to browse for more device documentation:
http://www.xilinx.com/xlnx/xweb/xil_publications_index.jsp?iLanguageID=1&category=-19202
http://www.altera.com/products/devices/dev-index.jsp
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top