AFE5812EVM: Different GND

Naik

Part Number: AFE5812EVM
Other Parts Discussed in Thread: AFE5809, AFE5812, AFE5809EVM

Hello TI people,

I have a question about the different ground in AFE5809/AFE5812 EVM.

It has three ground GND(Power GND), AGND and DGND(USB).

Now, From the schematic, I can see that Analog Ground is the Power ground. So would that be ok that if I connect AGND pins of an AFE5809/AFE5812 chip to normal ground and just keep two isolated ground on board, that will be GND and DGND.

Thank you.

over 7 years ago

0 Olu Sodipe over 7 years ago

TI__Expert 4145 points

Hi Vatsal,

That is a system decision. Separating grounds is usually done to prevent noise coupling across analog, digital, domains. Where on the AFE5809EVM do you see a Power ground?

Sincerely,
Olu

0 Naik over 7 years ago in reply to Olu Sodipe

Intellectual 720 points

Hi Olu,

That is true, it is mainly to prevent noise between analog and digital part.

On AFE5809EVM AnalogGND = Power GND so there is only two GND that I can see. Is it on purpose that EVM doesn't have it Analog GND separated? Because if we look in to AFE5809 datasheet there are pins for Analog GND.

Thanks.

0 Olu Sodipe over 7 years ago in reply to Naik

TI__Expert 4145 points

Hi Vatsal,

We generally recommend separating analog and digital grounds for our AFE devices. The schematics probably just need updating.

Sincerely,
Olu

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AFE5812EVM: Different GND