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Visitor eiselekd
Visitor
495 Views
Registered: ‎11-10-2018

Spartan6 3.3V input on a Bank3 with 2.5V VCC_IO

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I'm wondering weather connecting a 3.3V input to a Pin in a bank that is powered with 2.5V cause damage? 

I have a Enclustra MX2 Spartan6 XC6SLX45T board where I can select the VCC_IO voltage for Bank0,2,3 between 3.3V and 2.5V.
When running against a Cypress FX3 this VCC_IO is set to 2.5V.
However I want to monitor (input only) some GPIO's that are 3.3V, i.e. IO_L46N_M3CLKN_3 (G1) of Bank3.

Would it cause damage? Do the input level have to match VCC_IO? 

 

 

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1 Solution

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Xilinx Employee
Xilinx Employee
415 Views
Registered: ‎06-06-2018

Re: Spartan6 3.3V input on a Bank3 with 2.5V VCC_IO

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Hi @eiselekd ,

Yes, you can interface with diffrent VCCO. 

For Example, [1] If you are using LVCMOS Standard then, you need to ensure that VOH and VOL of transmitter are below the VIH and VIL of the reciver., for succesfull interfacing.

                       [2] If you are using LVDS Standard then, you can refer this AR#43989 , Since LVDS is not rail to rail voltage. If you satisfy the conditions mentioned in that you can interface with diffrent                               VCCO.

 

Hope you got the concept of interfacing, with different VCCO.

 

Regards,

Deepak D N

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4 Replies
Instructor
Instructor
469 Views
Registered: ‎08-14-2007

Re: Spartan6 3.3V input on a Bank3 with 2.5V VCC_IO

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For inputs, you can have 3.3V LVCMOS in a 2.5V powered bank.  See table 1-5 on page 39 of UG381.

-- Gabor
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Scholar u4223374
Scholar
439 Views
Registered: ‎04-26-2015

Re: Spartan6 3.3V input on a Bank3 with 2.5V VCC_IO

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@eiselekd In addition to what has been said above, if you look up DS162 (Spartan 6 datasheet) you'll find that the maximum recommended input voltage is 4V (commercial temperature range) or 3.95V (industrial/extended temperature range) - it has no dependence on either the I/O standard or any of the supply voltages. As a result, there should be no risk to just connecting the 3.3V signal directly.

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Xilinx Employee
Xilinx Employee
416 Views
Registered: ‎06-06-2018

Re: Spartan6 3.3V input on a Bank3 with 2.5V VCC_IO

Jump to solution

Hi @eiselekd ,

Yes, you can interface with diffrent VCCO. 

For Example, [1] If you are using LVCMOS Standard then, you need to ensure that VOH and VOL of transmitter are below the VIH and VIL of the reciver., for succesfull interfacing.

                       [2] If you are using LVDS Standard then, you can refer this AR#43989 , Since LVDS is not rail to rail voltage. If you satisfy the conditions mentioned in that you can interface with diffrent                               VCCO.

 

Hope you got the concept of interfacing, with different VCCO.

 

Regards,

Deepak D N

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Please reply or give kudo or Accept As a Solution.

-----------------------------------------------------------------------------------------------------------

Visitor eiselekd
Visitor
379 Views
Registered: ‎11-10-2018

Re: Spartan6 3.3V input on a Bank3 with 2.5V VCC_IO

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