5v Xilinx development board

To literally do that you'd probably have to find an old one, or one with level translators. One intended for a 5v PCI bus might have the level translators you need, just repurpose the PCI lines.

For many purposes though, you may be able to use a spartan 3 kit ($100) with series resistors to protect the FPGA input protection diodes from overcurrent. The FPGA outputs should be valid 5v TTL levels (though not valid 5v CMOS), though perhaps not as high a noise margin as you want.

Why wouldn't it be valid 5V CMOS? Doesn't it just have to be above 1/2 the supply voltage (ie. 2.5V)? Or are there CMOS inputs that really expect you to hit the rail?

Alan Nishioka

"native" 5v CMOS has a higher input threshold, which even 5v TTL may not reliably achieve - ie, it works on your breadboard but not in production, etc.

But a lot of 5v CMOS parts are made with a TTL compatible (2.4v I think) threshold, these are the ones with a "T" in their part number somehwere near the "C" - ie,"HCT", etc.

In a perfect world, it would be 2.5 V. In an imperfect world you need to accomodate non-symmetries. And you might like some noise immunity. Threfore 3 V should be the minimum High voltage, and 3.5 V is better. Peter Alfke

What size FPGA are you interested in? I make some boards that use the

5 V Spartan FPGAs. One board is for the XCS10 and the other is for the XCS30. Would either of these do you any good?

Jon

"Gary Pearman" schrieb im Newsbeitrag news:dump21$flh$ snipped-for-privacy@nwrdmz02.dmz.ncs.ea.ibs-infra.bt.com...

Our GOP_XC3S200 Mini FPGA module tolerates input voltages up to 7V at the GAL compatible DIL24 connector.

Optionally I/O's drive up to 5V by selectable pullup resistors. These features allows easy interconnection to 5V powered CMOS chips like PIC's, AVR's or others.

We use TI's 74CB3T3245 level shifters for this capability.

MIKE

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www.oho-elektronik.de
OHO-Elektronik
Michael Randelzhofer
FPGA und CPLD Mini Module
Klein aber oho !

Spartan II's are the last 5V IO tolerant Xilinx FPGA, and their 3.3V outputs are compatible with 5V TTL inputs (0.8 & 2.4V typically). CMOS logic typically has 20% & 80% thresholds, or 1V and 4V respectively. You can safely pull up a spartan 2 output to 5v externally without damaging the fpga. I think Avnet has some cheap dev boards for that family.

Andy Jones

Our Raggedstone1 product when used with the optional PCI I/O header (reuses PCI interface) gives 50 5V tolerant I/O. Price is £60 / US$108 (ex VAT - if applying) as a special offer currently if you join our newsletter list. £5 more if you don't. Worldwide shipping is £10. We also have a new module coming that will give 5V tolerant I/O from our DIl Headers if you want to run the card as a PCI card rather than just stand alone. Otherwise you can add your own stripboard with resistors as otherwise described.

John Adair Enterpoint Ltd. - Home of Broaddown4. The Ultimate Virtex-4 Development Board.