LT3081 Output voltage using a DAC

Hi,

I want to design a variable power supply (10 to 24V) as a part of a test equipment and want to use the LT3081 because of its nice current limiting and monitoring features. My idea is to use a buffered DAC and connect it to the SET pin. Is this possible?

Thank you!

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  • +1
    •  Analog Employees 
    on May 7, 2019 3:59 PM

    Thanks for the post.  You can drive SET on the LT3081 with a DAC, but keep in mind that the LT3081 and similar LDOs require that OUT and SET are always close to the same voltage.  That requirement is not well covered in the datasheets other than the +/- 25mA Abs. Max. SET Pin Current requirement in the case of the LT3081.  The LT3081 is the most rugged of the LT308X series of LDOs so the LT3081 is more tolerant in this area in comparison to the other LDOs but keeping the OUT and SET voltages about the same is a good practice even with the LT3081.  I show one approach to keeping OUT and SET the same in the image below:

    cust schem_2 scrubed_3.png

Reply
  • +1
    •  Analog Employees 
    on May 7, 2019 3:59 PM

    Thanks for the post.  You can drive SET on the LT3081 with a DAC, but keep in mind that the LT3081 and similar LDOs require that OUT and SET are always close to the same voltage.  That requirement is not well covered in the datasheets other than the +/- 25mA Abs. Max. SET Pin Current requirement in the case of the LT3081.  The LT3081 is the most rugged of the LT308X series of LDOs so the LT3081 is more tolerant in this area in comparison to the other LDOs but keeping the OUT and SET voltages about the same is a good practice even with the LT3081.  I show one approach to keeping OUT and SET the same in the image below:

    cust schem_2 scrubed_3.png

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