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Can I connect 5V ICs directly to the IOs of Xilinx Spartan3?

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gold_kiss

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Xilinx Spartan3 question

Hi all,
I am developing a board which uses Spartan 3 FPGA. Can I use 5V other ICs like SRAM, etc and connect directly to the IO's of Spartan 3 FPGA?

I guess spartan 3 is only capable to handle 3.3 V on its IO.
How do I solve this problem ...do I need to connect 3.3V SRAM also in worst case?
Thanks,
Gold_kiss
 

Re: Xilinx Spartan3 question

5V I/O operations are not supported. See Xilinx Spartan-3 FPGA Family Datasheet, topic: DC Electrical Characteristics, Absolute Maximum Ratings, Note 3.
 

Re: Xilinx Spartan3 question

Spartan-III does not support 5V IO. If you *need* to connect 5V-only devics, you'll need level converters or MOS switches.
 

Xilinx Spartan3 question

U can use 74lvt16244 or 74lvt16244 as a bridge between 3.3v and 5v device.
 

Re: Xilinx Spartan3 question

u can use 74125 level converters also between ur interfaces...but if interface lines are more than it will become ur design more comples as these level converters are not very very reliable....better go for "change device" option.
 

Re: Xilinx Spartan3 question

Xilinx web page gives a solution for CoolRunner-II devices. (xapp429)

That document will help you to get a solution.

If you have to convert a lot of signals, the best you can do is use 74VHC logic family or similar. This logic family works at 3.3V, but inputs are 5V tolerant.
 

Re: Xilinx Spartan3 question

you'd better use same voltage for fpga and other chips for voltage level

compatability, or you can use 74LVC logic to shift voltage level from 5V to

3V.

best regards







gold_kiss said:
Hi all,
I am developing a board which uses Spartan 3 FPGA. Can I use 5V other ICs like SRAM, etc and connect directly to the IO's of Spartan 3 FPGA?

I guess spartan 3 is only capable to handle 3.3 V on its IO.
How do I solve this problem ...do I need to connect 3.3V SRAM also in worst case?
Thanks,
Gold_kiss
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