Problem of AM1808 USB0 communication abnormality

g.f.

Guru 15510 points

Other Parts Discussed in Thread: AM1808

Hi,

We are using silicon rev2.1 AM1808.

The system is installed in indoor, but when temperature of ouside get colder, USB0 of AM1808 will stop.

So, I guess AM1808 errata Advisory 2.1.10 "USB0 PLL Mean Frequency Can Drift Across Large Temperature Swings"

matches to our USB problem.

From AM1808 errata Advisory 2.1.10, I understand as follow:

When the temperature swing large from the temperature when USB0 controller have been initialized,

PLL will be unstable and USB0 communication abnormality occurs because of that.

Is it correct?

And how large temperature swing range is it, which cause the PLL Drift?

best regards,

g.f.

over 9 years ago

0 Senthilkumar Srinivasan over 9 years ago

TI__Mastermind 43660 points

Hello G.f,

Yes, your understanding is correct.

The temperature swing range which cause PLL drift is explained in the errata as "More specifically, this advisory is most applicable in applications where the device is expected to operate outside the commercial temperature range of 0˚C to 90˚C. Operating outside the 0˚C-65˚C temperature range increases the susceptibility of the device to experience PLL drift, but does not mean that the application will always experience a failure in USB transmission".

One of our customer has already faced this issue and you can find the discussions in the below thread.

http://e2e.ti.com/support/dsp/omap_applications_processors/f/42/p/360069/1296190#pi239031349=1

Please note, this issue has been fixed in silicon revision 2.3.

Regards,

Senthil

0 g.f. over 9 years ago in reply to Senthilkumar Srinivasan

Guru 15510 points

Hi Senthil,

Thank you for the reply.

Let me ask again to make me sure.
If operating "inside" the 0˚C-65˚C temperature range but swings large
from the temperature when USB0 controller have been initialized,
does PLL drift occur?

best regards,
g.f.

0 Senthilkumar Srinivasan over 9 years ago in reply to g.f.

TI__Mastermind 43660 points

Hello G.f,

When there is temperature swing beyond the range 0˚C-65˚C, there might be a chance of PLL drift to occur.

Regards,
Senthil

0 g.f. over 9 years ago in reply to Senthilkumar Srinivasan

Guru 15510 points

Hi Senthil,

Thank you for the reply and sorry for the delay.
I understood.

best regards,
g.f.

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Problem of AM1808 USB0 communication abnormality