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Explorer
Explorer
7,103 Views
Registered: ‎09-16-2013

IO STANDARD

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HI all,

 

 

    what are the comparision between LVDS, LVTTL, LVCMOS and others...??

 

   

   Example: LVDS is high speed compared to others..

 

Thanks
Naveen G K
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Xilinx Employee
Xilinx Employee
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Registered: ‎08-01-2012

Re: IO STANDARD

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LVTTL is TTL based single ended IO standard. Little higher speed and more power consumption compare to LVCMOS.

LVCMOS is CMOS based single ended IO standard. Less power consumption compare to LVTTL.

LVDS differential IO standard. High speed, high distance, low power consumption compare to LVTTL, LVCMOS. The tradeoff is that it requires two pins & transmission lines for each signal. 

 

You can find more specification details about IO standards in https://www.jedec.org/ & http://www.jedec.org/sites/default/files/docs/jesd8c-01.pdf

 

Please note that maximum speed of any IO standard depends upon transmission line characteristics. So IBIS simulations are best choice to find out exact maximum speed & distance

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Scholar
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Registered: ‎06-05-2013

Re: IO STANDARD

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@naveengk14 Detailed expl is here

 

http://www.xilinx.com/support/documentation/user_guides/ug471_7Series_SelectIO.pdf

 

 

-Pratham

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Moderator
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Registered: ‎01-16-2013

Re: IO STANDARD

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@naveengk14,

 

LVDS: Low Voltage Differential Signaling

LVTTL: Low Voltage TTL

LVCOMS: Low Voltage CMOS

 

Check SelectIO user guide for 7 series (UG471) for more details:

http://www.xilinx.com/support/documentation/user_guides/ug471_7Series_SelectIO.pdf

 

--Syed

 

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Did you check our new quick reference timing closure guide (UG1292)?
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Xilinx Employee
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Registered: ‎08-01-2008

Re: IO STANDARD

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check this guide

http://www.xilinx.com/support/documentation/user_guides/ug381.pdf
Thanks and Regards
Balkrishan
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Xilinx Employee
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Registered: ‎08-01-2012

Re: IO STANDARD

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LVTTL is TTL based single ended IO standard. Little higher speed and more power consumption compare to LVCMOS.

LVCMOS is CMOS based single ended IO standard. Less power consumption compare to LVTTL.

LVDS differential IO standard. High speed, high distance, low power consumption compare to LVTTL, LVCMOS. The tradeoff is that it requires two pins & transmission lines for each signal. 

 

You can find more specification details about IO standards in https://www.jedec.org/ & http://www.jedec.org/sites/default/files/docs/jesd8c-01.pdf

 

Please note that maximum speed of any IO standard depends upon transmission line characteristics. So IBIS simulations are best choice to find out exact maximum speed & distance

________________________________________________

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View solution in original post

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Visitor
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Registered: ‎06-11-2016

Re: IO STANDARD

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Hi,

 

   I have a question related to LVCMOS I/O standards:

 

     - Lowering I/O power supply voltage (3.3V -> 2.5V -> 1.8V -> 1.5V -> 1.2V) saves the power consumption. Among LVCMOS33, LVCMOS25, LVCMOS18, LVCMOS15, LVCMOS12, which one has the highest operating frequency?

 

Thanks,

Toan

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Xilinx Employee
Xilinx Employee
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Registered: ‎08-01-2012

Re: IO STANDARD

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Impedance matching, cross talk, ground bounce and other transmission line related Signal Integrity(SI) parameters also play major role in addition to type of IO standard  to decide the maximum operating frequency. Best approach is to do IBIS simulations as per your board physics to find out exact maximum operating frequencies.

 

If there is no Signal Integrity problem then for LCMOS 12 operate for high frequencies for the ideal transmission lines because of fast raise and fall times.

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Visitor
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Registered: ‎06-11-2016

Re: IO STANDARD

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Thanks for the information.

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