AM335x PDN Analysis

Ned Dempsher

Other Parts Discussed in Thread: AM3358

I've been advised to do PDN analysis (I'll be using Ansys SIwave) by TI to ensure the decoupling approach in the datasheet will be adequate for my particular design along with all of my other parts but I need some additional information in order to properly do this. I need to be able to estimate transient current (to come up with target impedance) and required outside-of-the-package bandwidth to meet the target impedance for the various TI supplies. Does TI have any recommendations on what to design to for their supplies - bandwidth and transient current?

Thanks Very Much

Ned

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Hi,

I will ask the factory team is there is such information available.

0 Biser Gatchev-XID over 8 years ago in reply to Biser Gatchev-XID

TI__Guru**** 393215 points

Please post which processor you are asking about.

0 Ned Dempsher over 8 years ago in reply to Biser Gatchev-XID

Intellectual 260 points

Thanks Biser,

The part number is: AM3354BZCZA100.

The packaging design folks will probably know this information. When they do their own PDN design they make certain assumptions about this.

Thanks Again, Ned

0 Ned Dempsher over 8 years ago in reply to Ned Dempsher

Intellectual 260 points

Hi Biser,

Did you have any luck getting some information for me form the factory folks?
We are proceeding with analysis of our routed boards and want to release soon so this information would be a big help.
Thanks,
Ned

0 Biser Gatchev-XID over 8 years ago in reply to Ned Dempsher

TI__Guru**** 393215 points

I have asked again.

0 Ned Dempsher over 8 years ago in reply to Biser Gatchev-XID

Intellectual 260 points

Hi Biser,

Any word from them?

This is a related question.
Although my recommendation was to decouple to an area fill if at all possible the supply cap_vdd_rtc is decoupled using a 0.17" long by 12 mil. wide trace which goes from the processor to the decoupling capacitor (~4 mils. to the ground plane). Web trace inductance calculators indicate that this will be roughly 3uH of inductance. Since I don't know much about this supply I don't know whether this will be of concern. I do see that it is for a real time clock so I would think that you want this to be as low noise as possible, needing a fill, but don't really know. Do you think that this is a concern or do you see other customers getting away perfectly fine with this?

Thanks Bizer,
Ned

0 Ned Dempsher over 8 years ago in reply to Ned Dempsher

Intellectual 260 points

Sorry Bizer,
Same question would apply for VDD_ADC supply.
Ned

0 Biser Gatchev-XID over 8 years ago in reply to Ned Dempsher

TI__Guru**** 393215 points

These connections are not critical. 0.17" is perfectly acceptable.

0 Larbi Joubala over 8 years ago

Prodigy 220 points

Hi
I need also the bandwith of the switching current frequency for the am3358. I dont see any answer on this.

0 Troels Folke over 7 years ago

Prodigy 50 points

Hi Biser, need these numbers as well. Transient current & outside-of-package bandwidth.

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AM335x PDN Analysis