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

11 months ago

0 Frank De Stasi 11 months ago

TI__Guru 71865 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 11 months 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 11 months ago in reply to Catrin Simonson

TI__Guru 71865 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