LMR51610: INDUCTOR FORMULA IN DATASHEET VS EXCEL TOOL INDUCTOR CALCULATION

dharma raj

Prodigy 110 points

Part Number: LMR51610

Hello Team,

We chosen LMR51610 for an wireless AP design, below are the input, output requirement.

Vin: 48V

Vout: 28V

Iout : 0.6A

Fsw : 400KHz

Datasheet formula give us Inductance values of 171uH for above spec.

EXCEL TOOL suggesting Inductance value of 68uH.

Could you please clarify why there is huge difference in values?

Also could you please share us unprotected Excel calculation tool, becoz frequently the sheet is struct & not calculating the values as per the input.

Thanks

Dharma

over 1 year ago

0 David Baba over 1 year ago

TI__Mastermind 40060 points

hello Dharma,

will look into this and get back to you tomorrow with an update, thanks.

David.

0 dharma raj over 1 year ago in reply to David Baba

Prodigy 110 points

Hello David,

Any updates?

Regards

Dharma

0 David Baba over 1 year ago in reply to dharma raj

TI__Mastermind 40060 points

Hello Dharma,

I took a look into this and it appears that the calculation are calculated based of the output current of 1A. the input for your load requirements are only used for losses over the load range, but the inductor using IOUT = 1A not 0.6A.

Hope this helps,

David.

0 dharma raj over 1 year ago in reply to David Baba

Prodigy 110 points

Hi David Baba,

Excel tool from TI site is is not updating the values properly due to some trust issue with excel application. Could you please provide unprotected sheet.

Thanks

Dharma

+1 David Baba over 1 year ago in reply to dharma raj

TI__Mastermind 40060 points

Hello Dharma,

As mentioned, the spreadsheet is assuming full load current, and this cannot be adjusted. We are not permitted to unlock the spreadsheet. Please follow guideline in the datasheet for the correct value. We also have Webench to provide you with a suitable design also. Suggest using this tool for your design.

Thanks.

David.

0 dharma raj over 1 year ago in reply to David Baba

Prodigy 110 points

Sure. Thanks David Baba.

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LMR51610: INDUCTOR FORMULA IN DATASHEET VS EXCEL TOOL INDUCTOR CALCULATION