TUSB4041I-Q1: TUSB4041I-Q not function

Hi Ofer,

Remove pullup on TEST and pulldown on SMBUSz.

Regards,
JMMN

Hi JMMN,

I removed the TEST pullup and the SMBUSz pulldown.

The voltage on TEST now is 0 and SMBUSz is 3.01V but still  not function.

Please advice?

Regards,

Ofer

Is the upstream port connected to a host? What is the voltage at USB_VBUS and USB_R1?

Does the device have a solid ground plane connection?

Regards,
JMMN

Hi JMMN,

upstream connected 

USB_VBUS = 0.458V

USB_R1 = 0V   

VDD33 = 3.27V

VDD11 = 0V

The TPS74801 stop providing the 1.1V   it append after take out resistors connected to TEST and SMBUSz.

I check this on 2 boards and got same result something shortcut the VDD1.1  (the TUSB4041 temperature rise to about 40C).

Please advice ?

 

thanks

Ofer

HI Ofer,

I don't see any issues with the 1.1V rail in the layout, removing the pullup on TEST and pulldown on SMBUSz should have no effect on power consumption. Can you confirm nothing else was impacted? Is there a solid ground plane under the device?

Regards,
JMMN