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PMIC MMPF0100Z inductor selection

Question asked by vinod sharma on Dec 4, 2015
Latest reply on Dec 10, 2015 by David Diaz Marin

Hi,

 

From MMPF0100Z datasheet section 8.1.2 Bill of material selected inductor saturation current value is 4.5Amp for BUCK, SW1AB - (0.300-1.875 V), 2.5 A.

It seems that this current rating much overrated?

 

For a buck convertor with VIN = VINSW1x = 3.6 V, VSW1x = 1.2 V, ISW1AB= 2.5A, Eff= 80%, Fsw=2Mhz

 

is 0.5A. Thus Peak inductor current is 2.5+(0.5/2)=2.75A only.

 

Considering 30% derating 3.6Amp saturation current inductor should be OK.

 

Please let us know is this OK to select a inductor part as per above calculation. This is to reduce overall PMIC supply cost as our current requirement is much lesser than current available on each buck converter of PMIC.

 

Regards

Vinod

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