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AM3352：Not recognize USB

Kanae
Mastermind 9655 points
Part Number: AM3352
Other Parts Discussed in Thread: TPD2E001

Hi Support Team,

We have a defective board that does not recognize USB in a customer's mass-produced product
that is a business use printer.
The status is as follows.

-A problem occurred in the market where the PC did not recognize the product.
　 As a result of investigation, it was confirmed that the USB data signal line was shorted to GND.
　USB protection device: TPD2E001DRYR and CPU: AM3352BZCZ60.
-Confirm the waveform abnormality between the following pins of AM3352BZCZ60 by I-V characteristic.
　#N17-#N18
-Number of defect: 1 unit

The customer's consideration is as follows.
It is presumed that this event occurred due to the failure of the USB circuit of the CPU after the protection circuit was damaged.

-The output of the VBUS line when the USB connector is connected is normal, so there is no failure in the peripheral circuit.
-The USB data± signal is not being output. The USB data± signal was not output, and the DATA+ line was shorted to GND.

Check contents
(1) Short-circuit check
①Check that #3 and #4 of IC7004 (USB protection device) are short-circuited.　→The DATA signal line is shorted to GND.

(2) Check the peripheral circuits.
②USB0_VBUS input voltage
　 USB0_VBUS input voltage changes from 0V to 4.25V when the USB connector is inserted.　→Normal.
③IRQ_VBUS input voltage
　 Changed from 3.16V to 0V when USB connector is inserted.　→Normal.

(3) DATA communication waveform check
④Data signal is not output on NG board.　 →Short circuit of CPU or IC7004 is assumed.

(4) Identification of defective parts
⑤Remove IC7004 (to eliminate the cause) and check the actual device.　→Reproduction of symptoms.

Based on the above result ⑤ and the following circuit information, it is presumed
that the protection circuit has stopped functioning and the USB circuit on the CPU side has failed.

*Since the foot of the component was removed when removing "TPD2E001DRYR" from the board,
the characteristics cannot be confirmed.

Question
About CPU(AM3352BZCZ60)
1) Regarding the cause of #N17-#N18 short circuit, as in the case of TPD2E001 (ESD protection),
　is there a possibility of EOS due to exceeding the rated voltage?

<AM335x D/S Page-80>

2) What is TI's opinion on whether there are multiple occurrences?

Best regards,
Kanae

  • 0
    TI__Mastermind 27720 points

    Hello Kanae,

    1) Any excursion from the max operating conditions outlined in the datasheet could damage the device.

    2) A single excursion could damage the device. Multiple excursions increase the likelihood of device damage.

  • 0 in reply to -DK-
    Mastermind 9655 points

    Hi DK,

    Thank you for your reply.

    Regarding "Are there multiple occurrences?" in (2),
    the intent of this question was to find out if there are a number of similar occurrences.

    Just to make sure, am I correct in understanding that if a customer's system exceeds
    its operating conditions, there is a high possibility that such a phenomenon will occur?

    Best regards,
    Kanae

  • +1 in reply to Kanae
    TI__Mastermind 27720 points

    Hello,

    I have supported this device for ~10 years now and cannot recall seeing similar occurrences to what you are reporting so I think it safe to assume that this is an isolated incident. Yes, exceeding the max operating conditions outlined out in the DS is likely to cause device damage.