MDIC0 and MDIC1 resistor power for P2020

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MDIC0 and MDIC1 resistor power for P2020

1,641件の閲覧回数
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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1,634件の閲覧回数
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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1,614件の閲覧回数
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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1,635件の閲覧回数
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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