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LMR51450: Inductor saturation current

Kei Kuwahara
Expert 8120 points
Part Number: LMR51450


Hello team,

My customer is chosing inductor for LMR51450.

On the section 9.2.2.3 of the datasheet, it is stated that "The inductor saturation current must be higher than peak current limit level."

Question 1: Is peak current limit level, ISC (HS FET current limit)?

Question 2: If so, the inductor must have saturation current of 8A?

Question 3: What would happen, if inductor with saturation current of less than 8A is used, then load pulls more than 8A.  What would be the inductor current of LMR51450, A or B on the diagram below?

Best Regards,

Kei Kuwahara

  • +1
    TI__Mastermind 40310 points

    Hello Kei,

    Yes, the 8A is the typical peak current limit level of the HS MOSFET.  The worse case it is specified up to 9,6A.  If you are using a Ferrite core, its a hard saturation device that would saturate if the ISAT rating is lower that the max peak levels.  Suggest using a core that can withstand the worse case peak current limit levels.  if the core cannot and saturation occurs, the current in the high side FET could increase non-linearly and could cause potential failure in the device.

    Hope this helps.

    David.