hitheshn

USB2.0 signal Integrity

Discussion created by hitheshn on Aug 29, 2012
Latest reply on Aug 29, 2012 by Steve_McKinney

Any examples of USB high speed signal integrity using hyperlynx?

 

I am trying to simulate usb high speed from a MCU. I am not sure what to connect it to. For the time being i tried with LPC1850 mcu and a 90 ohm resistor and 5pf cap to ground from both D+ and D- lines.

 

But the problem is when I select high speed USB all I get is a 2 DC waves at the output. One at 2.8v and other at 0v

 

If I select full speed pins, I get waveforms as expected (12MHZ).

 

The MCU is SAM9G25. Series termination resistors are 22 ohms, TL impedance is 45 ohms.

FFS attached.

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