LM51581: Maximum feedback resistor

Atsushi Hirai

Part Number: LM51581

Tool/software:

Hi team,

My customer want to reduce the bias current for feedback resistor as much as possible.

What is the maximum resistor value TI recommend?

Best Regards,

+1 Moritz over 1 year ago

Hi Atsushi,

Thanks for reaching out.

Please have a look at the following document: https://www.ti.com/lit/an/slyt469/slyt469.pdf

If the feedback resistance is too high, the output voltage can become inaccurate depending on the current flowing in the FB pin.

This current is in the range of tens of nA. For your calculations you can assume a max. IFB of 50-80nA.

Best regards

Moritz

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