TPS23881: Please review the schematic, and have a question.

Hi Chase,

Thanks for reaching out!

Our PSE expert Brandon is traveling now. Please expect a delayed reply. Thanks for your patience.

Best regards,

Diang

Dear Diang,

Thank you for your support. Hope that he returns to the office soon.

And I got more information from my customer. Please check it too.

1. They made 6 sample PCBs, and 3 PCBs showed failure.

2. Sometimes the failure did not be seen even the power is off and on again, and suddenly they could see failure while they turn the power off and on repeatedly.

3. If they replace failure IC to new one, the PCB operates normally.

4. If the IC is dead, it is dead permanently.

Please check this issue. Thanks.

Best regards,

Chase

Hi Chase,

I am on business travel, I will reveiw your schematic by Monday COB next week.

If the port is shutting off, can you read the fault registers to better understand why the device is shutting off?

Also check your power on sequencing. Vpwr must clear UVLO rising condition prior to Vdd coming online. The device should be held in reset during this sequence. 

Also, confirm you are loading SRAM v15, which is the latest SRAM version.

Regards,

Brandon

Dear Brandon,

Thank you for your support.

Could you explain more about power on sequencing? what does it mean clear UVLO rising condition?

What is Vdd "coming online"?

Anyway the device should not be operational before Vdd is detected?

It is very good if you provide timing diagram about it.

Best regards,

Chase

Hi Chase,

Brandon is traveling now. Please expect a delayed reply. Thanks for your patience.

Best regards,

Diang

Dear Brandon, Diang,

Thank you for your support, and hope you had a good weekend.

Please let me know if there are any updates for the issue below. My customer is still waiting the review.

Best regards,

Chase

Hi Chase,

I will review these questions and provide feedback. Thanks for your patience!

Regards,

Brandon

Dear Brandon,

Please let me know if there are any updates about the review.

Best regards,

Chase

Dear Brandon,

Hope you had a good weekend.

Is there any updates about the review? My customer is still waiting the the review.

Best regards,

Chase

Hello Chase, 

We would need some more time to complete the review. We will keep you posted once the review has been completed. 

Regards,
Deepak 

Dear Deepak,

Thank you for your support.

It's been 20 days since I made a request. Please review faster.

Best regards,

Chase

Certainly Chase. 

Regards,
Deepak 

Hi Chase,

Thank you for your patience. From a HW perspective I do not see any issues occuring. 

We need access to the registers to see why the device is failing. Is customer loading SRAM upon boatup? Does the device reset? Do you have capability to do register dump?

Please capture VDD, RESET and VPWR waveforms upon this cycle to check the status for power off and power on.

Regards,

Brandon