MDIC0 and MDIC1 resistor power for P2020

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MDIC0 and MDIC1 resistor power for P2020

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toddreed
Contributor I

Hello,

I need to ensure that the MDIC resistors do not fail derated power limits.  What is the estimated power usage for a 40.2 ohm resistor on MDIC0 and MDIC1?

Thank you,

Todd

 

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toddreed
Contributor I

Hi Bulat,

Thank you for your response.  I currently have 0603 resistors in there that are rated for 0.1W max, but I have to derate them to 0.056W.  Is this OK, or should my derated max be > 0.1W?

Thanks,

Todd

 

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Bulat
NXP Employee
NXP Employee

Yes, it is OK. 'Maximum theoretical power' can be calculated as GVDD x GVDD / 40.2. This results in about 80mW for DDR2 and 56mW for DDR3. In fact the peak power dissipation would be less, so no problem with resistor's size.

Regards,

Bulat

 

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Bulat
NXP Employee
NXP Employee

Those resistors are used during hw calibrations, i.e. relatively short time. Theoretically possible peak power is less than 0.1W, so resistors size 0402 is ok.

Regards,

Bulat

 

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