LMR51430: Negative supply PCB review

Catrin Simonson

Part Number: LMR51430

Hi there,

I am attempting to design a -15V power supply using the LMR51430 in IBB configuration. Please see attached schematic and layout.

Before I submit it for manufacture, are there any issues that should be addressed?

Any support much appreciated.

-15V_B_Layout.pdf -15V_B_Schematic.pdf

over 1 year ago

0 Frank De Stasi over 1 year ago

TI__Guru 73235 points

Hello

Here are a few comments

1. You will need to damp the input filter with an aluminum electrolytic capacitor across C50

2. It is best to leave a place for a feedforward capacitor across R16

3. It is hard to see how the GND-B net is completed between the inductor and the ceramic output capacitors; it is best to have a close direct connection here.

I have attached an application note that may be helpful.

Thanks

1586.snva856a.pdf

0 Catrin Simonson over 1 year ago in reply to Frank De Stasi

Prodigy 50 points

Hi Frank,

Thanks for your feedback.

I've attached new docs showing the addition of an electrolytic across C50, a footprint to play around with feedforward caps, and adjusted the layout so that the output components in the GND_B net are much closer together.

This is looking a bit better?

layout-v2.pdf

+1 Frank De Stasi over 1 year ago in reply to Catrin Simonson

TI__Guru 73235 points

Hello

Yes, that looks better.

Keep in mind that you can always order the EVM for this device and configure for IBB to give you a little more confidence.

Thanks

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LMR51430: Negative supply PCB review