Buffer or 1:2 mux for RGMII with very low skew

Thomas Kofoed-Hansen

I need to have an fpga "listen" to RGMII trafic between processor and PHY. For that I need two hex buffers or 1:2 mux's with very low skew ( < 500ps ).

Processor and PHY use 3V3 but fpga can use both 1V8 or 3V3.

I would appreciate any suggestions as I haven't been able to find anything for days now.

over 9 years ago

0 James Lockridge19 over 9 years ago

TI__Genius 14485 points

Thomas,

All logic parts are guaranteed to have less than 1 ns skew for an equivalent load on each output. I'll see if I can find more information about which logic families have the lowest skew and what that value may be.

James

0 Thomas Kofoed-Hansen over 9 years ago in reply to James Lockridge19

Intellectual 550 points

Hi James,

thank you that would be very helpful. The biggest problem is that this parameter is mostly not specified. I also need to say that RGMII is runs 125MHz.

Thomas

0 James Lockridge19 over 9 years ago in reply to Thomas Kofoed-Hansen

TI__Genius 14485 points

Thomas,

From my understanding, parts in our LVC family should have a skew of less than 500 ps. The only hex buffer we have in the LVC family is SN74LVC07A-Q1. This is an automotive qualified part, so it might be a little more expensive than a catalog part. However we have dual, quad, and octal catalog buffers that may fit your needs as well.

If I find any more information about this, I will post it here.

James

0 Thomas Kofoed-Hansen over 9 years ago in reply to James Lockridge19

Intellectual 550 points

James

I'll look at you suggestions and see what I can do. Thank you for your input.

Thomas

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Buffer or 1:2 mux for RGMII with very low skew