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  • TI Thinks Resolved

LM43601: Small inductor and output capacitor footprint

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Replies: 8

Views: 151

Part Number: LM43601

Hello,

I have made a -5V inverter design with LM43601PWPR IC. But in the design, 27uH inductor and 150uF capacitor have a big footprint. I have successfully got -5V but this design conquers too much space on my PCB. How can I select the smaller inductor and capacitor components? 

Or do you refer any other design converting 7.4V to -5V with 0.5A with less than 300mm2 place on the board and less components? But main IC should be SOIC or other related packages, not as QFN type.

Thank you

  • Hi Alpaslan,

    I used the Webench design using your parameters. The example design uses a 22uH inductor and 56uF output bulk capacitor. The balanced design shows 240 mm2, but you can optimize your design depending on your flexibility on specs. 

    Thanks,

    Ethan

  • In reply to Ethan T:

    Could you share BOM file and simulation export?

  • In reply to AE104:

    For example, can I use the Digikey part no: 283-4591-1-ND inductor? It has a little bigger DC resistance value than the design.

  • In reply to AE104:

    Here is a link to the design. You can export the BOM and data their.

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

  • In reply to AE104:

    Hi Alpaslan,

    I believe that inductor is okay. Higher DCR means more loss and smaller size means high temperature rise for the same power dissipation. But at 0.5A, I do not believe thermals should be issue operating at room temperature.

    Regards,

    Ethan

  • In reply to Ethan T:

    Still inductor is big for my case. Do you suggest any design without inductor?

  • In reply to AE104:

    Hi Alpaslan,

    An inductor is required to use this power topology. I suggest you going to this webench link:

    https://webench.ti.com/power-designer/switching-regulator/select

    Here you can enter your parameters and customize your design as you like. You can select "small footprint" in the design considerations. The tool will suggest a couple of solutions.

    Hopes this helps,

    Ethan

  • In reply to Ethan T:

    Thank you Ethan!

    I did a new design by selecting less output current in WeBench, Thank you!

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