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I am working on a senior design project and am trying to embed an ATSAM3X8E (Here is the Application Sheet PDF) micro-controller into a system my team is designing. What is the pourpose of incorperating an inductor into the VDDUTMI (USB 3-3.6V input) and the VDDANA (for ADC and DAC supplies) ? I konw as a senior I should probably know this, but a little help is welcome.

Also, for the number 2 red circle, is that a symbol for a polarized capacitor? I am not used to this representation.

EDIT: Also, why is there no value for the resistor?? What does 1R mean?

(This above schematic can be found on page 4 of the application note file.)

enter image description here

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1 - The two 10 uH inductors are RF chokes which keep external noise picked up on the UTMI+ interface (such as USB cables) from getting back into the ADC and causing noise.

2 - Yes, those are all electrolytics, presumably tantalums.

3 - The symbols are indeed resistors, 1R stands for 1 ohm. A common convention for resistors is to use XRXX to indicate X.XX ohms, XkXX for X.XX kohms, XMXX for X.XX Mohms, etc.

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The inductor is probably used to improve noise filtering on the supply lines

Since the two electrodes of the capacitor are shown differently, this implies to me that it is a polarized capacitor (electrolytic), although I don't think I've seen that particular symbol before.

For some reason the resistor symbols don't appear in my browser. However, I expect that "1R" means the resistor value is 1 Ohm.

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