TUSB4041I: Crystal won't start oscillating: device descriptor request failed on any OS.

Dario Moscardi

Part Number: TUSB4041I

Hello TI-Team,

I am guessing about a solution with my TUSB4041I application. When I connect the device to the USB port i have "Unknown USB Device: device descriptor request failed".

With the oscilloscope i can see that the device tries to start up the crystal with multiple square pulses at very low frequencies (see attached img) but it won't oscillate.

I am quite sure about the load capacitance calculation and i also tried many values without getting to a solution.

It seems like the device is trying to do a test on the crystal peripheral or something like this.

Is there anything else that can cause problems to the crystal? The datasheet says that it has to oscillate at 1.8V but the charge pump loads the crystal at a maximum of 1.42V.

Thanks in advance,

Dario Moscardi

over 5 years ago

0 JMMN over 5 years ago

TI__Guru 60870 points

Hi Dario,

I'm sending you a friend request, can you send me your schematic directly? Just the hub portion is fine.

Regards,

JMMN

0 Thuan Vu over 5 years ago in reply to JMMN

Intellectual 460 points

Was there a solution to this question? I think I'm experiencing something similar.

0 JMMN over 5 years ago in reply to Thuan Vu

TI__Guru 60870 points

Hi Thuan,

Can you share the hub portion of your schematic? Are you seeing a very low voltage swing on the crystal too?

Regards,

JMMN

0 JMMN over 5 years ago in reply to JMMN

TI__Guru 60870 points

Working with Thuan in another open thread, closing this one.

0 Thuan Vu over 5 years ago in reply to JMMN

Intellectual 460 points

Typically not seeing any oscillations but sometimes see the low voltage oscillations like above.

0 Dario Moscardi over 5 years ago in reply to Thuan Vu

Prodigy 115 points

Hello,

Sorry for my late reply but i was involved in another project.

My problem was caused by poor soldering on the ground pad under the IC.

Solved this issue, i am trying to stress the component in many situations but it keeps working well and the startup always ends without problems.

The only situation that can cause the controller to fail during startup is a wrong voltage on the 1V2.

By my opinion, you should verify that soldering and the minimum output current on the LDO. Otherwise, the output voltage could be greater than you expected.

I hope this could help you,

Dario Moscardi

0 JMMN over 5 years ago in reply to Dario Moscardi

TI__Guru 60870 points

Thanks for the update!

Regards,

JMMN

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TUSB4041I: Crystal won't start oscillating: device descriptor request failed on any OS.