How to choose DC resistance parameter of a USB 2.0 common mode choke?
Drivers impedance is generally lower than the USB cable impedance giving some tolerance to DCR for the CM choke.
But a higher impedance CM choke like 500 Ohms with 5 Ohms DCR will greatly improve CMRR and should not interfere much with signal integrity yet give better immunity. This should improve signal damping as well but may limit BW on the fastest USB3.
I’d have to look at the details and your specs for the above.
Depending on your USB speeds and interference, 270 Ohms @ 100 MHz 0.5 Ohm DCR may be adequate. But &gt; 500 Ohms @ 5 DCR will be better if SRF is beyond your BW.