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LP8860-Q1: how to calculate inductor rating?

Chen Bogey8
Mastermind 9990 points
Part Number: LP8860-Q1

Hi Sir 

Enclosed file is my calculation way. is it correct? is any thing i need to notice?

My customer want to change inductor form CDRH127NP-220MC to NPIM74P220MTRF(smaller). is it ok?

Voltage : 46.2V Vin 8~19V.

Current : 150mA

 

 

Inductance

DCR

Isat

Irms

CDRH127NP-220MC

22uH

0.043

 

3.6A

NPIM74P220MTRF

22uH

0.19

3.5A

2A

ubLP8860.xlsx

  • 0
    TI__Intellectual 2180 points
    Hello,

    We don't recommend using lower current rating inductor, from min and max conditions Vin =8V, Vout 46.2V, the recommendation is to use even higher 4A-5A inductor rating if possible. Your calculations are ok but please note that these calculations do not consider efficiency, so we recommend at least 30% or higher than calculated value to allow for some headroom.