TPS659037: TPS6590378: LDOUSB output on power OFF sequence

Satoshi

Guru 19585 points

Part Number: TPS659037
Other Parts Discussed in Thread: AM5728

When testing power off sequence on TPS6590378 + AM5728, LDOUSB output become a little increased voltage (0.6V) after reset assert for about 3ms.

Is these behavior any problem?

If possibility to problem, please let me know any improve point or reference circuit.

・Waveform is attached below;

・Extracted circuit is below;

　※VDOUSB output is only connecting AM5728.

Best regards,

Satoshi

over 3 years ago

0 Daniel W over 3 years ago

TI__Genius 13216 points

Hi Satoshi-san,

Thank you for the questions.

How many boards is this issue appearing on?

Thanks,

Daniel W

0 Satoshi over 3 years ago in reply to Daniel W

Guru 19585 points

Hi Daniel

Thank you for reply,

This issue is appearing five boards.

When these boards power off, this issue is appearing every time (100%).

Best regards,

Satoshi

0 Daniel W over 3 years ago in reply to Satoshi

TI__Genius 13216 points

Satoshi-san,

Please refer to this application note on using the TPS6590378 + AM5728 for a reference schematic to ensure all connections are correct.

https://www.ti.com/lit/pdf/sliu011

Thanks,

Daniel

0 Satoshi over 3 years ago in reply to Daniel W

Guru 19585 points

Hi Daniel

Thank you for reply,

In conclusion, is these behavior any problem and not recommended?

Customer design is refereeing and based on above application note and design guide.

Best regards,

Satoshi

0 Daniel W over 3 years ago in reply to Satoshi

TI__Genius 13216 points

Hi Satoshi,

This behavior does not exceed any maximums on the TPS6590378 and it is able to discharge the overvoltage through internal pulldown resistance. So it should not be a problem to the TPS6590378. However, I cannot inform you of its effect on the AM5728. I would recommend starting an E2E thread inquiring about that device specifically in order to get more information.

Thanks,

Daniel W

Power management

Power management forum

TPS659037: TPS6590378: LDOUSB output on power OFF sequence