Hi all, Sorry if this is not exactly about open cores, but I think you people can answer my question the best. I was wondering what tools any of you who have worked with BGA packaged devices (namely FPGA) have used in prototyping your design. I don't have, nor can I really justify to my superiors, a rework station. Is there a cheap & dirty method to working with BGA such as using solder paste or BGA socket adapters? I will be working with a Fine Pitch (1mm) Thin BGA FT256 FPGA. Thanks, Colin -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums.cgi/cores/attachments/20031215/52075fa7/attachment.htm

Hi!

There is a "hobby" project: http://wwwbode.cs.tum.edu/~acher/bga/index.html This was told me 1-2 years ago on the comp.arch.fpga newsgroup. There was a huge discussion at this time. Have a look at the archives. I would recommend to use a normal SMD oven. This shouldn't be too difficult to get. Probably you can ask some personell at the nearest university that you can use theirs. Put a lot of flux at your PCB, adjust the FPGA as carefully as possible and then heat it up and wait. As the FPGA has solder bumps you don't really need to put solder paste at the PCB. The most difficult thing is getting the wires away from the FPGA. Use at least a 4 layer PCB with fine pitch and small vias. I've been told that a GND and VCC plane is highly recommended. Bye Hansi -- Johann Glaser Johann.Glaser at gmx.at> Vienna University of Technology Electrical Engineering ____ http://www.johann-glaser.at/ ____

Hi Colin, well I am afraid I have to dissapoint you. BGA's are a pain to work with if you do not have the right equipment and right experience. A BGA socket adaptor is one solutions though, but you would have to get the socket assembled by someone. Are you going to exchange your FPGAs a lot? Given you should just put an FPGA on a board, I would contact an assembly house and have them do it for me. That is by far the cheapest way to go. If you are going to exchange your FPGA to other devices I would have the same assembly house mount the socket instead. That will save you a lot of grief in the long run... Good luck! -- Best regards Björn Olsson Vice President Production -------------------------------------------------------------------- InformAsic AB / Hugo Grauers gata 5B / SE-411 33 GÖTEBORG / Sweden Tel: +46 31 68 54 90 Fax: +46 31 68 54 91 Mobile: +46 733 75 97 01 E-mail: bjorn.olsson at informasic.com Home: www.informasic.com Colin F. MacKenzie wrote:

On Mon, 15 Dec 2003 13:52:56 -0400 "Colin F. MacKenzie" cmackenzie at colinmackenzie.net> wrote: CFM> Hi all, Sorry if this is not exactly about open cores, but I think you CFM> people can answer my question the best. I was wondering what tools any CFM> of you who have worked with BGA packaged devices (namely FPGA) have used CFM> in prototyping your design. I don't have, nor can I really justify to my CFM> superiors, a rework station. Is there a cheap & dirty method to working CFM> with BGA such as using solder paste or BGA socket adapters? I will be CFM> working with a Fine Pitch (1mm) Thin BGA FT256 FPGA. Usually there is no need to rework FPGAs. When designing, my strategy is to connect as many signals to the FPGA as possible. I usually end up not using half of them but so far I managed to avoid board respins for FPGA pinout reasons. If you are thinking of blowing devices, this in fact is not so easy to do. Modern FPGAs can take a lot of stress! The only cases when I needed rework was when an assembly house would fail to do good job in the first place. It is a good idea to have first prototypes X-rayed, might save some debugging time. To summarize, have your boards assembled and inspected by a good assembly house and you won't need any rework. -- Mikhail Matusov misoma at rogers.com>

Colin F. MacKenzie wrote:


You're better off sending your stuff to a third-party assembly house.
There are plenty of them, and it's usually not very expensive.

There *are* BGA sockets, they are, however, very expensive (depending on
size as much as thousands of dollars) and take a lot of board real
estate (as much as a very large heatsink.) My employer, Transmeta, uses
them to be able to quickly test multiple chips in the same board.

-hpa

Xilinx offers a board for around $500.00 USD that has a ZIFF type socket for a BGA. I have used their Virtex BG560 prototyping board and it's very nice for starters. Good luck. Chris ----- Original Message ----- From: Bjorn Olsson Bjorn.Olsson at I... > To: Discussion list about free open source IP cores cores at o... > Date: Mon, 15 Dec 2003 19:38:39 +0100 Subject: Re: [oc] Prototyping BGA devices
your



Sweden

Xilinx offers a board for around $500.00 USD that has a ZIFF type socket for a BGA. I have used their Virtex BG560 prototyping board and it's very nice for starters. Good luck. Chris ----- Original Message ----- From: Bjorn Olsson Bjorn.Olsson at I... > To: Discussion list about free open source IP cores cores at o... > Date: Mon, 15 Dec 2003 19:38:39 +0100 Subject: Re: [oc] Prototyping BGA devices
your



Sweden