Switching regulator PCB design

[mrknownothing]

Hi,
I am doing a layout for a switching regulator IC. The IC has 2 separate grounds. Where should I short these grounds on the board? What should be the reasoning and thought process for thinking about this.

Thanks

 

[shaiko]

What regulator are you using?
please post the datasheet

 

[mrknownothing]

What regulator are you using?
please post the datasheet

TPS61026 from TI

 

[Tosspot]

Hi,
I am doing a layout for a switching regulator IC. The IC has 2 separate grounds. Where should I short these grounds on the board? What should be the reasoning and thought process for thinking about this.

Thanks

For general ground segregation rules have a read of the first pages of this article by Analog Devices titled 'Grounding In High Speed Systems' (the same principles apply), and check the diagram on the second page:
**broken link removed**

And you should also read at least the first few pages of this one titled 'Analog Layout and Grounding Techniques'
**broken link removed**

For something specifically about switching regulator layout, this one by Maxim is a good overview that also addresses your questions directly:
**broken link removed**

And this one by Texas Instruments is also good
**broken link removed**

And finally in the datasheet for the TPS61026 there is a paragraph on layout specifically relating to this chip on page 17

 

[mrknownothing]

Hi Tosspot,
Thank you very much for the wonderful links. Really clarified a lot of things. I was thinking to connect the AGND and PGND at the board's VIN terminal to prevent any switching current to flow through the analog ground, but the articles told me just the opposite and explained the reasoning very nicely.