AM335x USB termination

Hi Biser,

Regarding the VDDA1P8V_USB pin, we understood that in all cases a 1.8V power
supply should be connected to this pin.

But one of customer has unfortunately designed their custom board with VDDA1P8V_USB pin unconnected (NC).
And currently it is difficult to design a new board...

Could you please let us know what kind of effect will it cause if VDDA1P8V_USB is not connected to 1.8v 
even though if we don't use USB ?

Will there be a severe effect on the AM335x operation?

Best Regards
Prad

I cannot say. If they haven't followed the design guidelines TI cannot guarantee proper device operation.

Hi Biser,

Thank you for the quick response.

Actually they have connected VDDA1P8V_USB0 to 1.8V
only VDDA1P8V_USB1 pin and VDDA3P3V_USB0/1 is left unconnected.

As mentioned in the datasheet VDDA1P8V_USB0 would effect USBPHY and PER DPLL,
can we assume VDDA1P8V_USB1 doesn't have that much effect?

Best Regards
Prad

The Schematic checklist clearly states what connections should be made: http://processors.wiki.ti.com/index.php/AM335x_Schematic_Checklist#If_USB0_or_USB1_is_not_used... If your customer has not followed this I cannot help. Please do not ask me what will happen if design guidelines are not followed. This is customer's responsibility.