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dangcaominh , 02-03-2025, 04:15 AM

Hello, I am currently drawing this DP83848IVV ethernet PHY schematic and I follow from Phil's lab design that the line TD+, TD-, RD+, RD- has a parameter set with impedance constraint from 90 to 110 ohms and matched net lengths 20ps rules. Also, I saw from other design that these four lines have 49.9 ohms pull-up resisitor to +3v3 rail. My question is: is it needed in my design with these rules already? I am new to signal integrity and impedance matching technique. Pls help

dangcaominh , 02-03-2025, 04:20 AM

Whether or not to place termination resistor on MDI line

QDrives , 02-03-2025, 03:56 PM

As shown on page 69 of the datasheet https://www.ti.com/lit/ds/symlink/dp83848i.pdf?ts=1738570939676 too?

dangcaominh , 02-03-2025, 04:00 PM

So the answer is yes, I should place it, right?

QDrives , 02-03-2025, 04:03 PM

Correct.

dangcaominh , 02-04-2025, 03:48 AM

Thanks