LM43601: Small inductor and output capacitor footprint

AE104

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

over 4 years ago

0 Ethan T over 4 years ago

TI__Expert 3835 points

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

0 AE104 over 4 years ago in reply to Ethan T

Expert 1090 points

Could you share BOM file and simulation export?

0 AE104 over 4 years ago in reply to AE104

Expert 1090 points

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.

0 Ethan T over 4 years ago in reply to AE104

TI__Expert 3835 points

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

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

0 Ethan T over 4 years ago in reply to AE104

TI__Expert 3835 points

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

0 AE104 over 4 years ago in reply to Ethan T

Expert 1090 points

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

0 Ethan T over 4 years ago in reply to AE104

TI__Expert 3835 points

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

0 AE104 over 4 years ago in reply to Ethan T

Expert 1090 points

Thank you Ethan!

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

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LM43601: Small inductor and output capacitor footprint