AM437x GP EVM schematic Rev.1.5b question

RWIN

Hello,

While I was looking at the GP EVM schematic, I found something that I don't understand.

On sheet n°3, if you look at the VDDS_CTM pin (AD12 pin), you can see that there's a ferrite bead between VDDS_CTM pin and the 1.8V power supply.

I searched in the AM437x datasheet and I found that this pin is supposed to be a VDDS pin even though "AD12 and AD8 are not connected to VDDS in the device, but they are required to be connected to 1.8-V VDDS on the board".

Is the ferrite bead important or not ?

Is the ferrite bead the thing that prevent AD12 pin to be directly connected to the others VDDS pins ? If so, why the AD8 pin is not connected to a ferrite bead ?

Thanks for any answer !

RWIN

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi,

I will ask the factory team to comment. They will post directly here.

0 RWIN over 9 years ago in reply to Biser Gatchev-XID

Intellectual 390 points

Thanks Biser, I'm looking forward to hearing from them.

0 peaves over 9 years ago in reply to RWIN

TI__Guru 64745 points

The note in the data sheet is trying to explain how terminals AD8 and AD12 connect to separate internal VDDS power rails and must be connected to the same power source as the other VDDS terminals. The AD12 terminal also powers some analog functions and the ferrite bead isolates this terminal from noise generated by the other VDDS terminals.

Regards,
Paul

0 RWIN over 9 years ago in reply to peaves

Intellectual 390 points

Thanks for the answer Paul !

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AM437x GP EVM schematic Rev.1.5b question