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LM76005-Q1: LM76005-Q1

Anu Shetty
Prodigy 50 points
Part Number: LM76005-Q1

Hello ,

We are planning to use LM76005-Q1 BUCK Converter in our design for 24V applications. Please find the parameters details mentioned below

Parameters-

Vin max  =  36V

Vin typ   = 24V

Vout       =  12v

Iout       =  3.5A

When we perform the manual calculations by considering data from the data sheet, Tj values is going high due to high Pd , but with the web design files attached above for the reference we don’t see high Power dissipation with parameters mentioned above,

Below i am attaching both ,

1)Manual Calculations for typical value(24V)

2)Web Design Calculations.

Manual Cal-pd.xlsxWBOperatingValuesDesign32.csv

Query 1->What is the efficiency to be considered for the output current of 3.5A

Query2-What is the thermal resistance value to be considered

 

  • +1
    TI__Expert 6960 points

    Hi Anu,

    The RθJA varies with board size, please see figure 10-2 in the datasheet. You can use a lower thermal resistance depending on your board size. We recommend using our webench tool for designs. 

    Regards,

    Rahil

  • +1 in reply to Rahil Ajani
    Prodigy 50 points

    Hi Rahil,

    There is one more query related to efficiency,the efficiency considered in webbench tool for 3.5A output current is 96.3%.but according to the datasheet graph of efficiency curve it should be around 92% to 93%.

    which efficiency value should i consider, web bench tool efficiency value or the efficiency value from datasheet graph.

  • +1 in reply to Anu Shetty
    TI__Expert 6960 points

    Hi Anu,

    Please consider the webench efficiency data since that is personalized to your exact parameters

    Regards,

    Rahil