TPA2026D2: 01H register wasn't reset to default value even if toggling SDZ

Hi Luis-san,

I apologize for late reply.
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- How much time is SDZ toggling? I mean, how much time is SDZ in low state and in high state? Has customer increased the low state time?
My customer increased low state term around 1 minute however the issue coudn't be improved.

 - Does customer applies SWS = 1 before toggling the SDZ pin?
Yes, shutdown sequence is the following.

1) write 0x03 to 01H register: disable right and left amplifiers
2) write 0x23 to 01H register: SWS = 1
3) wait 80 us
4) toggle SDZ high -> low -> high
5) read 01H register however the value is still 0x23 (abnormal state)
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Best Regards,
Yaita

Luis-san,

>Does customer face this issue the 100% of times?
No, we don't have reproduced the issue by intention so far.
The device that has "abnormal state" was returned from end customers after mass production. I heard the incidence rate is about 200ppm.
"Abnormal state" means 01H register can't be reset to default value (C3h) even if toggling SDZ, it is still 23h until removing power supply (AVDD, PVDD, PVDDR).
The power supply (AVDD, PVDD, PVDDR) is applied at all times except removing or empty battery in their system.

We can't find root cause why the device went to the abnormal state, so would like to confirm the following shut down sequence is recommended or not.
1) write 0x03 to 01H register: disable right and left amplifiers
2) write 0x23 to 01H register: SWS = 1
3) wait 80 us
4) toggle SDZ high -> low -> high
5) read 01H register however the value is still 0x23 (abnormal state)

Do you recommend omitting steps 2) and 3) in this case?
If so, I suggested to my customer the sequence and have my customer see how it goes aftertime.

Best Regards,
Yaita

Luis-san,

>Were you capable to see this issue on the returned units?
I didn't see the issue, my customer saw it on returned system that TPA2026D2 is mounted.

>Do you know if this issue persists if the TPA2026D2 is replaced?
If removing power supply (AVDD, PVDD, PVDDR) the issue was removed (normal operation), so we think replacing the device goes to normal operation.

>The shut down sequence is correct and it shouldn't generate an issue.
Thank you for your confirmation. I understand.

Let me contact you again when we will need your additional support.

Best Regards,
Yaita

Luis-san,

I always appreciat for your kind support.

Best Regards,
Yaita