LT3063 load regulation

Hi All,

We are considering LT3063MPMS8E#PBF (adjustable version) to generate 2.5V with 3% accuracy. We realised that the accuracy is severely impacted by the load regulation parameter of this IC. Load regulation is calculated to be 37.5 mV max (9 mV * 2.5/0.6) similar to the calculation provided in page 12 of the datasheet. Is my interpretation of datasheet correct?

Also, 9mV max is provided when load is varied from 1mA to 200 mA. However in our application, maximum load current is only 50 mA. For maximum load current of 50 mA, what should we consider for load regulation. Is it 9 mV or less?

Attached is the screenshot of load regulation value from datasheet of LT3063.

Thanks

C.Pradeep

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  • 0
    •  Analog Employees 
    on May 22, 2020 8:15 PM

    Thanks for the post.  I will attempt to answer your question but I will also forward this post to the design group and I will post again if I am significantly corrected about anything.

    I think you are doing the load regulation calculation correctly and also you can assume that your load regulation will be better in proportion to the range of the  load regulation specification that you utilize.  You may want to include some margin since I doubt if all load regulation can be thought of as an I*R type voltage drop phenomena.  Don't forget about temperature.  I show some Load Regulation versus temperature curves from the LT3050 datasheet in the image below.  The LT3050 is a different part, but load regulation may get worse for the LT3063 with termperature in a similar fashion. 

    LT3050 dagtasheet load reg_0.png

  • 0
    •  Analog Employees 
    on May 22, 2020 8:55 PM in reply to ARad

    The design group did contact me and said you could use 4.5mV instead of 9mV conservatively in your calculation since your load current is only 50mA.  The design group also pointed out the Load Regulation graph from the LT3063 datasheet in the image below, which I did not originally notice.  Note the curve shows that the ADJ version has better load regulation since the output voltage is sensed externally.

    LT3063 datasheet load reg_0.png

  • Thank you ARad. Just to reconfirm. Considering 4.5 mV for 0.6 V output, for 2.5Vout regulator, error due to load regulation is 18.75 mV (i.e., 0.75%). Is this correct?

  • +1
    •  Analog Employees 
    on May 27, 2020 12:54 AM in reply to Pradeep.C

    That is correct.

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