LM5017: 3.16k as FB2 resistor results in 5.4V Vout

flavio

Part Number: LM5017

Hi Daniel,

I am changing R228 from 3.16k to 2.87k (see the attached schematic page). Using 3.16K the output I measure across the board is 5.4V. Although on paper calculation using 3.16K results in Vout=5V, but on the board I measure 5.4V, so I worry stressing the logic too much.

Switching R228=2.87 on paper results in Vout= < 5V, but I measure 5V across the board, which is what I need.

Is changing from 3.16K to 2.87K ok in our design attached, I am keeping all the other components the same.

over 4 years ago

0 Ankit Gupta95 over 4 years ago

TI__Expert 4555 points

Hello Favio,

Is this the same issue we are talking about in two different E2E thread: https://e2e.ti.com/support/power-management/f/196/t/875750

Please let me know.

Best Regards,

Anki Gupta

0 flavio over 4 years ago in reply to Ankit Gupta95

Intellectual 410 points

Hi Anki,

It is the same issue. LM5017 is on a custom board. Using R228=Rfb2=3.16k and Rffb1=1k i measure 5.4V. if I change R228=Rfb2=2.87k, I measure 5V. Just want to make sure after the change the regulator is still is stable. can you please verify?

lm5017aa.pdf

0 Ankit Gupta95 over 4 years ago in reply to flavio

TI__Expert 4555 points

Hello Flavio,

Please send your schematic and layout on my email Id: a-gupta1@ti.com, will get you connected with the device expert.

Since we are going to solve this problem offline. Please close the thread on this forum, so that TI won't monitor this query on two different forums. Thanks!

Best Regards,

Ankit Gupta

Application Engineer.

Power management

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LM5017: 3.16k as FB2 resistor results in 5.4V Vout