TPS56339: Device sensitivity to inductor DCR

Edward Peek

Part Number: TPS56339
Other Parts Discussed in Thread: TPS54302

I have a question about the TPS56339 Buck Converter and the sensitivity to 200 milliOhms of inductor DC resistance. Is this a problem?

My question stems from experience with the TPS54302 and its' destruction when I used a higher DC resistance versus one under 100 milliohms. And your simulations seem to use a DC resistance under 100 milliohms.

I am a little tight on space and trying to stay in a 4040 package (LQH44PH220MPRL, 384 mOhm DCR destructive to TPS54302)

Guidance would be appreciated.

over 3 years ago

0 Young Zhao over 3 years ago

TI__Genius 9280 points

Hi Ed,

May i check with you about what's the VIN-VOUT-Loading ?

Normally larger DCR would affect the efficiency as much power on DCR. if assume Iout=3A, DCR=384mohm, the voltage drop on DCR is larger than 1V , so the Vin should be larger than Vout , maybe 2V for some margin .

BRs,

Young

0 Edward Peek over 3 years ago in reply to Young Zhao

Prodigy 20 points

Hi Young,

The Vin is 20V and the Vout is 5V in one circuit and 13V in another. The 5V circuit is the most sensitive; the current demand is less than 300 mA.

Thanks for your assistance,

ps. Sorry, this reply was sent through email originally.

0 Young Zhao over 3 years ago in reply to Edward Peek

TI__Genius 9280 points

Hi Ed,

No problem .

I will close this post first, please let me know if there is any thing we can help .

BRs,

Young

0 Edward Peek over 3 years ago in reply to Young Zhao

Prodigy 20 points

Why are you closing this post?

My question is still open: Is the TPS56339 sensitive to inductor DCR? If so, what are the recommendations?

0 Young Zhao over 3 years ago in reply to Edward Peek

TI__Genius 9280 points

Hi Ed，

Sorry for donnot get your question in your last reply.

As i mentioned in my first answer ，there would be no concern from my side based on 20vin-5/13 vo with less than 300ma loading.

About the sensitive,could you help describe more clearly about it? Or you can just send the details to my email young-zhao@ti.com.

Br,

young

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TPS56339: Device sensitivity to inductor DCR