IMX28 DCDC_VDD unused

[dgotfroi]

Hello everybody,

I desgin a board with an IMX28 and I only use 3V3 and 1V8 from the IMX power supply. I didn't use VDD1P5 neither VDDD.

So, how can I connect VDD1P5 ? Can I leave it unconnected without capacitors or do I need to connect it to capacitors (10n, 100n 1u, 10u and 25u) ?

And what about VDDDx and DCDC_VDDD :

- Can I leave them unconnected ?

- Do I need to connect them together but without capacitors ?

- Or do I need to connect them together and with capacitors ?

This is my current schematic :

Do I need C1-C5 and C14-C21 ?

Many thanks for your help.

[igorpadykov · Accepted solution]

Hi Damien

VDDD can not be left unconnected.

VDDD provides power to the digital core such as CPU and clocks,

as described in application note AN4199 (Rev.1 , 03/2013)

"Using the i.MX28 Power Management Unit and Battery Charger".

http://www.freescale.com/files/dsp/doc/app_note/AN4199.pdf

VDD1P5 can be left unconnected, if unused.

Best regards

chip

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[dgotfroi]

Hello,

Many thanks for your answer.

So, I will remove C1 to C5 and leave VDD1P5 unconnected.

It answers my question.

Thank you