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iMX6 VDD_HIGH_CAP ESR

Question asked by markwilliams on Mar 19, 2019
Latest reply on Mar 19, 2019 by igorpadykov

Hi,

 

I have a question regarding the technical bulletin EB814 for the iMX6 which states that the bulk capacitance, 10uF, on VDD_HIGH_CAP must be minimum 85mohm.

 

We are using an 0402 MLCC for the bulk capacitance and have added a footprint for a series resistor. However studying the ESR for such capacitors the ESR naturally varies with frequency. For example a Murata part has minimal ESR at 1MHz of around 4mohm but rises either side of this.

 

I have looked on reference designs but it seems that these pre-date the bulletin so have no fix. I would therefore just like assurance for my design on the spec - is 85mR the minimum across the frequency spectrum? At what frequency does the minimum ESR matter?

 

What would you recommend in terms of this pin - should I add 0.1R series resistor with the ceramic cap?

 

Kind regards, Mark

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