LPC55S28 USB HS Receiver sensitivity Test

[hskating]

NXP team
When I used the LPC55S28 chip to make a product using high-speed usb, after the software function was basically completed, I began to conduct USB authentication Test, and encountered a problem about the Receiver sensitivity Test Reference. It looks something like this:
usb2.0 electrical test failure: High-speed devices must implement a transmission envelope detector that does not display suppression (that is, reliably receive packets) when the receiver differential amplitude exceeds 150mV.
Pass limit: <= 200.000 mVDevice
Please see the attachment for details.

How do I fix this?
I sincerely hope that the NXP team can give me advice and support in this regard.
Thank you from the bottom of my heart.

[Alice_Yang · Accepted solution]

Hello @hskating 

Please check the hardware as follows:

Check the D+/D- differential lines. Ensure they are kept away from high - frequency sources such as clock lines and power switches.

Please check the capacitor on the USB_VDD pin. Place it close to the chip. You can refer to the schematic of the lpcxpresso55s28 - evk board.

Allocate a separate ground layer for the USB PHY.

You can also use a USB analyzer to monitor the communication process signal. 

BR

Alice