TPS7A3001-EP: Can not get stable output

user6024592

Part Number: TPS7A3001-EP

Hi，there

I‘m trying to get -12v output by TPS7A3001 but my output is not stable. Some times it outputs -12V （much times it can keep less than 2 second）but some times it drops to -4V or lower from -12V and constantly changing.

My input is -13V from another voltage regulators(it's output is correct).

This is my PCB layout,U17 is the TPS7A3001

Q:Is there any mistakes in my design？How can I slove it？

Thanks for your help。

over 4 years ago

0 Daniel Hartung over 4 years ago

TI__Mastermind 21965 points

Hello,

I noticed the output capacitance you are using is quite low.

The datasheet recommends at least 10 uF.

Please increase the output capacitance to get a more stable output.

Thanks,

Daniel

0 Daniel Hartung over 4 years ago in reply to Daniel Hartung

TI__Mastermind 21965 points

I realized the "10 nF" I saw may be 10 uF as the schematic is hard to read.

Can you confirm the output capacitance?

Thanks,

Daniel

0 user6024592 over 4 years ago in reply to Daniel Hartung

Prodigy 30 points

Thanks for your reply.

The output capacitance I use is a 10uF parallel with a 100nF.

0 Daniel Hartung over 4 years ago in reply to user6024592

TI__Mastermind 21965 points

Hey,

Are you able to get me a screen shot of the output when this change from -12 to -4 happens?

Thanks,

Daniel

0 Daniel Hartung over 4 years ago in reply to Daniel Hartung

TI__Mastermind 21965 points

Hey,

Did this issue resolve itself?

Thanks,

Daniel

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TPS7A3001-EP: Can not get stable output