USB Simulation with Transmission Cable...

[bharatsmile2007]

Hi,

i need to simulate the LS/FS driver of USB 2.0 with a transmission line.Can any one tell me the below transmission line is correct or not?

T50 FS_DP_OUT1 0 OUT_DP 0 Z0=45 TD=2.6n L=0.5m

TD was decided form the spec 5.7ns/m for FS.Any Approx of 0.5m was taken for length.Z0 is the single ended impedance.

Thanks

 

[FvM]

I understand, that you are using individual transmission lines for DP and DN. This would still meet the common mode impedance
range of 21..39 ohm, but not achieve the typical value of 30. You may want to use a combination of three transmission lines to model
the typical charateristics more exactly. The difference only matters for the single ended signalling elements and can be most
likely neglected with 0.5 m cable.

 

[bharatsmile2007]

Thanks FVM..

can i use the same transmission line model for Low Speed operation also?

T50 FS_DP_OUT1 0 OUT_DP 0 Z0=45 TD=2.6n L=0.5m