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LM2576S-ADJEVM: LM2576S-ADJEVM

prabhu k
Prodigy 125 points
Part Number: LM2576S-ADJEVM
Other Parts Discussed in Thread: LM2576

Hi TI Team,

In our design we are using LM2576S-ADJ/NOPB part, I am unable to get WEBENCH® Designer  for LM2576S-ADJ/NOPB.

Can you please suggest Cout and inductor values ?

Input voltage range= 10V-28V

Input capacitor Cin= 2, 220uF @ 180mOhm input capacitors.

We are striving for 2 years of life at 70 ambient.  With 2, 220uF capacitors and Vout  5V @1.3A DC load current results in a 0.78A ripple at 52kHz on the input capacitor...estimate. 

Re-evaluate the inductor and output capacitors based on the new limitations ?

  • 0
    TI__Expert 7700 points

    Hello,

    Please refer to the following Webench design: https://webench.ti.com/appinfo/webench/scripts/SDP.cgi?ID=C63303FE9DF4B00C

    I think, I have your parameters listed, but you can adjust as needed. Please set the device for 3A. I know you will not be using 3A, but when sizing the inductor, it is important to choose the inductance value based on the full load capability of the device for stability purposes even if you plan to use a lighter load.

    Best regards,

    Ridge

  • 0 in reply to Ridge Lahti
    Prodigy 125 points

    Hi Ridge,

    Thank you for your support,

    I am unable to open your link, please share once again

  • 0 in reply to prabhu k
    TI__Expert 7700 points

    Hello,

    Please see attached link:

    https://webench.ti.com/appinfo/webench/scripts/SDP.cgi?ID=C63303FE9DF4B00C

    Best regards,

    Ridge

  • 0 in reply to Ridge Lahti
    Prodigy 125 points

    Hi Ridge,

    Still, I am unable to open below link, can you please share schematic and BoM(Webench)

    webench.ti.com/.../SDP.cgi

  • 0 in reply to prabhu k
    TI__Expert 7700 points

    Hello,

    The link will work if you copy the text into a web browser. I have attached the requested images.

    Best regards,

    Ridge

  • 0 in reply to Ridge Lahti
    Prodigy 125 points

    Hi Ridge,

    Please check below image regarding inductor and Cout values, is this fine ?

    And also attached pdf file of LM2576 power design from WEBENCH, please review and let me know any changes required.

    LM2576 design from TI.pdf

  • 0 in reply to prabhu k
    TI__Expert 7700 points

    Hello,

    The inductor value is a bit high. Generally, it is recommended to size the inductor for the full load of the device (3A), rather than the load you plan to operate at (1.3A) for better stability in a converter. However, if Webench is producing a stable design, then it should be OK. Please keep in mind that the inductor you choose in your application must have a saturation current rating of at least the maximum current limit rating of the LM2576 as listed in the Electrical Characteristics table in the datasheet. If the inductor saturates, the device will not be able to function properly.

    Best regards,

    Ridge