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Best price per I/O

I'm looking into a crosspoint switching application where it appears FPGA's are the best choice even though I won't use much of the internals. What I'm looking for is the best price per I/O pin of relatively fast parts. Newer releases of FPGA seem to target better price per logic cell rather than I/O so I've already noticed that from Xilinx I can do better with Spartan 2e than Spartan 3 in terms of cost per I/O pin. Obviously smaller parts in each family also giver better price per I/O because there are more I/O's per logic cell. Any suggestions for a better price would be appreciated.

Also the reason I'm not currently looking at CPLD's is that the application requires soft upload and I don't want parts with limited programming cycle life (EPROM or FLASH based).

256 I/O's per part is a good match for the design although even at this level I will need multiple parts. Right now I'm more interested in what family to use for the best price per I/O and then I'll pick the device size that fits best.
Reply to
Gabor Szakacs
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Hi Gabor,

You may want to consider the Altera Cyclone EP1C4 device. This device uses a staggered pad ring to deliver more I/Os (and consequently fewer LEs) in a given die size than the other Cyclone members. The device is available in

324- and 400-pin FBGA packages giving you 249 and 301 user I/Os to work with respectively. I know nothing about pricing beyond what is on our main website ($7.50 based on 250K unit volumes in 2004 time frame) -- I'd suggest you contact an Altera distributer or sales rep to investigate cost.

Go to

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for more details on the Cyclone family.

Regards,

Paul Leventis Altera Corp.

Reply to
Paul Leventis (at home)

Given your application, you may want to review a paper presented at the 2003 FCCM conference:

A High I/O Reconfigurable Crossbar Switch

Steve Young, Peter Alfke, ColmFewer, Scott McMillan, Brandon Blodget, and Delon Levi

The procedings are available through the IEEE, but maybe you can get a copy directly from the authors, who are all at Xilinx. Peter Alfke is a regular on this news group.

Philip Freidin Fliptronics

Reply to
Philip Freidin

The Spartan 3 also uses a staggered IO ring.

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on page 4 of 5 lists all of the package IO combinations.

For the 320 and 456 pin packages, we have 221, and 333 IOs. Prices ranges from $6.50 to $12 in large qty right now (2004).

Austin

Reply to
Austin Lesea

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