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LMR23625: out of recommended feedback resistor value

Shinichi Inoue
Guru 21861 points
Part Number: LMR23625


Dear Specialists,

My customer is considering LMR23625 and has a question.

I would be grateful if you could advise.

---

When I confirmed webench, feedback resistor top(Rfbt) is 332kohm.

On the other hand, datasheet P. 12 says  "RFBT in therange from 10 kΩ to 100 kΩ is recommended for most applications."

332kohm is out of the recommended range, is there no problem?

Also I'd like to know why 332k and 22.1k is selected.

---

I appreciate your great help in advance.

Best regards,

Shinichi

(1)Webench_LMR23625_22VIN_16V2.5A_20180424.pdf

  • 0
    TI__Mastermind 25590 points
    Shinichi,

    Both the datasheet and WEBENCH will work. It's a matter of design specs. 10k to 100k will reduce noise susceptibility but they will consume more power than 332k. But some applications don't like resistors over 100k. Clearly the engineers who made the datasheet vs WEBENCH picked different values within their margins of "acceptable values" but in reality, both are fine.

    332k and 22.1k are selected to divide 16VOUT down to the 1V reference.

    -Sam
  • 0 in reply to Samuel Jaffe
    Guru 21861 points

    Hi Sam,

    Thank you for your reply.

    I understand it's no problem to use 332k and 16k.

    It is a trade-off between noise and current consumption.

    I'll share this information with the customer.

    I appreciate your great help.

    Best regards,

    Shinichi