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LM25149: How to use FB pin of LM25149

Part Number: LM25149

Hi Team,

I think the FB pin of the LM25149 can change the voltage, but do you have any data on the responsiveness?

Also, is it possible to output a negative voltage by connecting a negative voltage power supply?

Best Regards,

Tom

  • Hi Tom,

    The FB pin is the internal reference point of the device and also how the device regulates the output voltage. The top and bottom resistors are picked for a output voltage so that the FB voltage is 800mV. 

    Any buck device can be configured to be an inverting buck boost where the device will regulate to a negative output voltage given a positive input voltage.

    For more details please refer to app note : https://www.ti.com/lit/an/snva856b/snva856b.pdf

    Regards,

    Jimmy