What for are the 1.2, 2.5 and 3.3V used in Xilinx FPGA?

[VLSI_CHE]

i want to know what for are the 1.2,2.5 and 3.3V useful in an FPGA.

 

[mrflibble]

Interface to external logic standard with those voltages?

 

[sanju_]

this are used for interfacing externals as mrflibble said...
in xilinx FPGA their are different banks each bank has different voltages
for example in spartan-6 bank-0 and bank-2 has 2.5v, bank-123 has 1.5v some banks has 3.3v.

 

[FvM]

All FPGAs need at least a low core voltage (e.g. 1.2 V) and a high auxilary and IO supply voltage (e.g 2.5 or 3.3 V). IO voltage supplies are required according to the application and have to be added, if not already present for the basic FPGA supply, e.g. 3.3 V for general logic, 2.5 V for LVDS, 1.8 or 1.5 V for RAM interfaces. As said, you have to select a supply voltage for each bank of IO pins. Simple designs can use an unified supply voltage for all IOs, typically 2.5 or 3.3 V.

 

[VLSI_CHE]

ohk now i understood that each of the voltages given to the FPGA are for specified banks in it. i am using sparton 3 for now . so could anyone tell me the voltages used for it , the 1.2,2.5, and 3.3 used for the same reoson?

 

[FvM]

the 1.2,2.5, and 3.3 used for the same reoson?

Yes. Do you have a particular development board? The IO voltage assignment is usually fixed for a specific board.