TUSB8041: TUSB8041 no function after power on!

Hello Hossein,

Please check the thermal pad connection under the hub has sufficient solder.  Most assembly issues with the TUBS8041 are related to insufficient thermal pad connection.

Regards,

JMMN

Hello JMMN,

the thermal pad has solid connection with the ground.

I checked the board again and in some cases the VBUS 5V was present but the USB connection was not  recognized.

I removed the BATENx pin pulled up to deactivate the Battery Charge support and the VBUS 5V was present but the USB connection was not  recognized.

Thank you

Best regards

Hossein

Hello JMMN,

another question, is the power up Timing hier correct:

3V3 first and then 1V1?

I measured that the GRSTz signal was high with/after 3V3 but 1V1 came after the two.

Thank you.

Best regards

Hossein

Hi Hossein,

Can you confirm that there is enough power on the board and there is no drooping on the 3.3V/1.1V or VBUS rails?

The GRSTz should not go high until after the 3.3V and 1.1V rails have ramped or the device will not get a proper reset.

Regards,

JMMN

Hi JMMN,

As you can see, Foto, the 1V1 is present (yellow) and the GRSTz (blue, capacitor on pin 50 1uF) is present as well with 1V1. But it schuld be high after min. 3ms.

And there is enough power on board. LMR33640 24V --> 5V, TPS62827ADMQ --> 3V3 and TPS54218RTE --> 1V1.

Thank you

Best regards

Hossein

Please increase the 1 uF capacitor to a larger value (2.2 uF or 4.7 uF).

Can you confirm that the reset is the issue, by manually resetting the hub and confirming the hub connects properly?   You can just short GRSTz to ground briefly.

Hi JMMN,

With 2.2 uF and 4.7 uF, we have already done but the signal increase is only flatter.

And with connection the GRSTz is already done. After connection the GRSTz to the ground the HUB is OK!

I send you the device production ID. You check it if it is OK.

Thank you

Best regards

Hossein

Hi Hossein,

The larger cap would increase the GRSTz ramp time, which should extend the GRSTz low during the 1.1V ramp.  How many boards are you seeing this issue on?  Have you tried replacing the unit?

Regards,

JMMN

Hi JMMN,

It doesn't work with larger cap too. 8 from 18 boards have tis issue. The unit is already fixed on board so we can't move it.

Best regards

Hossein

Does the hub show up as connected to the host and just the downstream ports do not work?  Can you share what the host reports (Device Manager or USBVIEW.exe for Windows or USBMON for Linux).  

Regards,

JMMN

Hi JMMN,

we use now external RST signal and its work.

Thanks for support.

Best regards

Hossein