TPS51200: TPS51200 datasheet (rev.D) : Keep total REFOUT Capasitance below 0.47uF

Akihisa Tamazaki

Part Number: TPS51200

Hello team,

TPS51200 datasheet at page 4 was changed as below picture.

In the datasheet rev.D. "keep total REFOUT capacitance below 0.47 μF" was added.

Q1) Why was it added?
Q2) In my customer condition, total REFOUT capacitance is 10 μF. What is the concern?

Your advise would be so appreciated.

Best Regards
Akihisa Tamazaki

over 3 years ago

0 Qian Chen over 3 years ago

TI__Mastermind 24075 points

Hi Akihisa,

We did simulation across process, voltage and temperature variation.

The simulation shows the Refout voltage may have stability issue at corner case if total capacitance is larger than 0.47uF.

TPS51200 has been released for many years and it is being used in large quantity. We know the refout capacitance is larger than 0.47uF in some customer's design, however so far no customer report there is stability issue.

If customer is working on new design, we would suggest to keep capacitance below 0.47uF.

For their released design, it is low risk to keep existing capacitance value if they don't see stability issue.

Thanks

Qian

0 Akihisa Tamazaki over 3 years ago in reply to Qian Chen

TI__Genius 10915 points

Qian-san,

Thank you for your comment.
Let me ask you again off line if the customer has some questions.

Best Regards,
Akihisa Tamazaki

0 Katsu Matsunaga over 3 years ago in reply to Akihisa Tamazaki

TI__Expert 7730 points

Hi Qian-san,

I have a question on this topic.

This capacitance limitation (<0.47uF) is for near refout pin of TPS51200, right?

my customer design have 0.1uF in side of TPS51200, and some capacitors in DDR memory side, total capacitance is larger than 0.5uF.

Is this out of datasheet description?

Thanks and best regards,

Katsu

0 Qian Chen over 3 years ago in reply to Katsu Matsunaga

TI__Mastermind 24075 points

Hi Katsu,

The 0.47uF is just a recommendation.

We tested TPS51200EVM with 10uF cap on REFOUT and don't see issue.

It is almost no risk to keep the existing cap on released project.

Thanks

Qian

0 Katsu Matsunaga over 3 years ago in reply to Qian Chen

TI__Expert 7730 points

Qian-san,

Thank you for your reply.

Let me confirm one.

The recommendation is for total capacitor on REFOUT line, right?

Best regards,

Katsu

0 Qian Chen over 3 years ago in reply to Katsu Matsunaga

TI__Mastermind 24075 points

Katsu-san,

Yes, it refers to the toal capacitance on REFOUT line.

Thanks

Qian

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TPS51200: TPS51200 datasheet (rev.D) : Keep total REFOUT Capasitance below 0.47uF