LM76005-Q1: LM76005-Q1

Anu Shetty

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.xlsx WBOperatingValuesDesign32.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

over 2 years ago

+1 Rahil Ajani over 2 years ago

TI__Genius 9460 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 Anu Shetty over 2 years ago in reply to Rahil Ajani

Prodigy 60 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 Rahil Ajani over 2 years ago in reply to Anu Shetty

TI__Genius 9460 points

Hi Anu,

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

Regards,

Rahil

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LM76005-Q1: LM76005-Q1