Saturation current of inductor?

Hello,

Do you know what is the saturation currenmt of this 3mH inductor?

(MCBF7344-302KU)

https://www.farnell.com/datasheets/1289012.pdf


(the datasheet does not say......the bit i am interested in is the slope-off after the 1 Amp point)

I don't really believe that you want to operate the 0.4 A inductor beyond 1 A, simply considering resistive losses. Short pulses with very low duty cycles may be an exception.

Bobin core inductors have generally a soft saturation characteristic according to their large air gap. The inductance won't drop to zero in heavy saturation. You can try to locate other manufacturer coils (e.g. Coilcraft, Wuerth) with a more detailed specification.

Thanks, but how do i know that Multicomp won't in the future, update this part to the same thing but using a non-gapped core?.....which would mean it saturating far more aggressively.

(i.e. supposing i wish to operate it above 1 amp for short duty cycles as you say.)

The bobbin core shape is a fundamental design parameter. Changing it means to make a completely different part. You should rather expect discontinuation of the component. Wuerth has a coil with similar specification, but even less information. If you want to more, you need to measure it yourself.

but you can have a bobbin core with gap, or a bobbin core without gap

In a standard bobbin core, an additional air gap won't matter much. The in-air part of the magnetic path is on the outside.

When the complete core is saturated, the inductance will be still reduced to perhaps 20 or 25 %.

grizedale said:

Hello,

Do you know what is the saturation currenmt of this 3mH inductor?

(MCBF7344-302KU)

https://www.farnell.com/datasheets/1289012.pdf


(the datasheet does not say......the bit i am interested in is the slope-off after the 1 Amp point)

Click to expand...

Depending on the type of inductor (chip inductor, power inductor) we may specify an Isat, Irms, or IDC current.

Saturation current (Isat) is the current at which the inductance value drops a specified amount below its measured value with no DC current. The inductance drop is attributed to core saturation.

RMS current (Irms) is the root mean square current that causes the temperature of the part to rise a specific amount above 25°C ambient. The temperature rise is attributed to I2R losses.

DC current (IDC) is the current value above which operation is not recommended without testing the component in its intended application.

For some inductors Isat is lower than Irms. The core saturates before the component temperature reaches the performance limit. In this case we may specify only the Isat as it is the limiting factor. For many inductors, Isat is higher than Irms. In these cases we may specify only Irms and the temperature rise above ambient. In many cases, we specify both Irms and Isat current to illustrate which measurement is more critical. IDC is specified typically when Irms greatly exceeds Isat.

The datasheet that you have mentioned provides us with IDC values i.e. 0.28A

for curve between inductance and IDC, Isat can get 0.4A, normally we indicate Isat which inductance drops off 10% or 20% based on the Idc.