TPS65381A-Q1: SDN6 Instability

Christian Sämann

Part Number: TPS65381A-Q1

Tool/software:

Hello I'm using a TPS65381A-Q1 and I'm looking at the SDN6 and VDD6 nodes, but it looks like there is a instability.

Any Idea what could be the reasons for this? I selected the PMIC surrounding components according to datasheet.

Thanks in advance.

3 months ago

0 Michael Hernandez 3 months ago

TI__Expert 5190 points

Hi Christian,

The things that comes to mind for me are the ground connection and possibly instability on the input supply. Check to make sure that all of the ground pins have continuity to a common ground. After that check to see how stable the voltage is on the VBAT pins.

Best,

Michael Hernandez

0 Christian Sämann 3 months ago in reply to Michael Hernandez

Prodigy 10 points

Hi Michael,

Thanks for the quick response I will directly look into your points.

BR Christian

0 Michael Hernandez 3 months ago in reply to Christian Sämann

TI__Expert 5190 points

Great. Let me know if you need any more help.

0 Christian Sämann 3 months ago in reply to Michael Hernandez

Prodigy 10 points

It looks like the ESR of the VDD6 preregulator was a bit too low. We used 120mOhm for 44uF but this was not enough. Once we increased the ESR a bit the controller shows now instability.

0 Michael Hernandez 3 months ago in reply to Christian Sämann

TI__Expert 5190 points

Hi Christian,

Good to hear that you fixed the issue and thank you for posting your solution on here.

Best,

Michael Hernandez

Power management

Power management forum

TPS65381A-Q1: SDN6 Instability