LM5085: LM5085

Ali Khan

Part Number: LM5085
Other Parts Discussed in Thread: LM25148, LM5148, LM5146

Hi, I need help in choosing a buck converter IC for the following design requirements. Input = 10 to 60V output = 8.4, 12.4,16.8V respectively(using FB resistors probably) Output current = 10A I also need help in reference design either from Webench or EVM. I checked LM5085 but it's webench do not work for these requirements. EVM also has not similar specs.
Size is very important so i need low BOM count.

I have questions though about EVM design.
Is it advisable to follow the EVM design and change according to the above need? If yes then what particular components i should focus on for the above requirements other than FB resistors.
Thanks

3 months ago

0 David Baba 3 months ago

TI__Mastermind 28660 points

Hello Ali,

If you need an output voltage above and below the input voltage, you will need to use a buck boost converter. I will reassign your enquiry to the correct product line who can advise using a different part as this device will not work. Thanks.

David.

0 Ali Khan 3 months ago in reply to David Baba

Intellectual 850 points

I don't need boost.

The input will always be high than output.

For example, for 16.8V, it will be 20V or more

0 EricLee 3 months ago in reply to Ali Khan

TI__Mastermind 48511 points

Hello Ali

16.8V * 10A = 168W. This power / current level is excessive for the non-synchronous buck converter to handle without special cooling method.

You will need a large heat sink and/or an additional cooling fan to make this happen with non-synchronous buck.

-EL

0 Ali Khan 3 months ago in reply to EricLee

Intellectual 850 points

Hi @EricLee

What other solution you suggest for me?
I also designed another board with LM25148 for 15A current that is probably a synchronous buck converter.
Can you suggest some synchronous buck converter with very low bom count?

This is what i am looking to design but in small size.
DC Dc

0 EricLee 3 months ago in reply to Ali Khan

TI__Mastermind 48511 points

Hello Ali

Based on the size of your board, LM25148 (synchronous buck) is a good choice if your maximum input voltage is less than 42V. This device provides a higher performance at lower cost.

Please create a new post if you have a question about this LM25148 device. Thanks.

-El

0 Ali Khan 3 months ago in reply to EricLee

Intellectual 850 points

No,
I don't want to design with LM25148. I said, i already designed the board with it. Now i need input voltages upto 60V at least.

0 EricLee 3 months ago in reply to Ali Khan

TI__Mastermind 48511 points

Hello Ali

We also have LM5148 which can handle up to 80V https://www.ti.com/product/LM5148

-El

0 Ali Khan 3 months ago in reply to EricLee

Intellectual 850 points

Is there any reference design or WEbench design available for it?

0 EricLee 3 months ago in reply to Ali Khan

TI__Mastermind 48511 points

Hello Ali

I guess we don't have.

-EL

0 Ali Khan 3 months ago in reply to EricLee

Intellectual 850 points

What about any other chip like 5146 or similar category?

0 EricLee 3 months ago in reply to Ali Khan

TI__Mastermind 48511 points

Hello Ali

LM5146 can handle up to 100V.

-El

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LM5085: LM5085