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TPS74901: TPS74901: When input=3.3V and output 1.8V, how to configure Vbias?

Jimmy Gong
Expert 3490 points
Part Number: TPS74901

Hi team,

As we know that the VBias must be 1.75V above Vout.

In this case, Vbias need at least > 3.35V(1.8V+1.75V = 3.35V). but the board doesn't have 5V source.

Could we use resisters to divide 12V source to 5V for VBias? If not, do you have any suggestions for this application?

BR,

Jimmy

  • 0
    TI__Mastermind 38115 points

    Hi Jimmy,

    Using a resistor divider could work, but the output voltage can be unreliable unless the resistors are sized to have at least 10mA through them or more, given the BIAS pin current of 1mA (typ) or 2mA (max). A more robust and accurate way to do it would be to either use another regulator for it, or use a shunt voltage reference. 

    Regards,

    Nick