TPS65911: Starting up of LDO5

K.Hamamoto

Guru 12155 points

Part Number: TPS65911

Our customer are evaluating TPS659114 with i.MAX6.

http://www.tij.co.jp/jp/lit/ug/swcu181c/swcu181c.pdf

And they found the unknown waveform on output of LDO5 when it startup.

(Configuration)

(Observed waveform)

There some over shoot. Is that normal?

The overshoot is disappeared if the no load condition.

However the overshoot is still maintain even if the input cap is increased and output cap is decreased.

If the overshoot is normal, is that problem for i.MAX6?

Please let me know any concerns about this issue.

Regards,

Koji Hamamoto

Regards,

Koji Hamamoto

over 8 years ago

0 Jayanth Kruttiventi over 8 years ago

TI__Intellectual 1360 points

Hamamoto san,

I have assigned your query to TPS65911 expert and he will get back to you soon. Can you please let us know how much load is present during LDO turn on.

Regards,
Jay

0 K.Hamamoto over 8 years ago in reply to Jayanth Kruttiventi

Guru 12155 points

Hi

I am sorry. I did not confirm to the customer about that current.
However you had confirmed the configuration(connections) with i.MAX6 on the following document. Have you ever seen that kind of behavior on that board?

Our customer found the waveform at the connection with i.MAX6 as same as your board.

Is that behavior no problem for TPS659114?

Regards,
Koji Hamamoto

0 Richard Solarski over 8 years ago in reply to K.Hamamoto

TI__Genius 10885 points

Hamamoto-san,

The absolute max for VDD_HIGH_IN is 3.6V, and this overshoot does not appear to exceed that value.

VDD_HIGH_IN ultimately regulates VDD_HIGH_CAP, so that capacitance and the subsequent loads will also be contributing to this current.

Best Regards,
Rick S.

0 K.Hamamoto over 8 years ago in reply to Richard Solarski

Guru 12155 points

Hi

Thank you for your support.
I understood.

Regards,
Koji Hamamoto

Power management

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TPS65911: Starting up of LDO5