TPS63000: How to reduce the Switching Noise?

Rene Lima

Part Number: TPS63000

Hi team,

I'm using TPS63000 as a 3v3 and 5v power supply in a new project. So, in the first batch, many PCBs failed the power supply, with the TSP getting in short-circuited. I'm trying to understand why it happened.

So, I observed a large switch noise on the inductor pins.

Vin=3.8v
Vut=3.3

Pin L1

Vin=3.8v

Vout=5v

Pin L2.

The datasheet shows the max and min voltages for L1 and L2 pins. The spikes above are higher than the limits, so, can they burn the TPS?

How can I reduce these spikes? Could you review my design below? Basically, the 3v3 and 5V power supplies have the same layout just the feedback resistors are different.

L2 part number: LQM2HPN3R3MG0L

Thanks!

over 1 year ago

0 Stefan Schauer over 1 year ago

TI__Mastermind 47941 points

Hi Rene,

thank you for using the E2E forum.

The expert for the TPS63000 is not in the office this week but he will reply as soon as possible once back next week.

Best regards,

Stefan

0 Rene Lima over 1 year ago in reply to Stefan Schauer

Prodigy 50 points

Hi Stefan,
Thanks for your reply. I will be waiting.

0 Stefan Schauer over 1 year ago in reply to Rene Lima

TI__Mastermind 47941 points

+1 Tao Zhang over 1 year ago in reply to Rene Lima

TI__Mastermind 25840 points

Hi Rene,

Below is some advices to your original layout.

Pour over the GND of input/output caps, but not connect them with some traces--this will help to reduce the spikes.
Pour over the GND of device, but not connect them with traces or vias--this will help to reduce the spikes
Move the via of FB path after the C77--this will make your FB path more clean

BTW, mostly, the spikes you got with oscilloscope are not actual ones because there will be some coupling between your board and probe. you can find the spikes will change with the direction of probe and the smallest you get will be more close to real spikes.

Also, we will share our recommended layout in the datasheet as below. sometimes you can take them as ref in your design.