Minimum current value of the 10 uH Inductor for DCDC

[Susan_cfx]

Hi,

Our company has produced a batch of BLE products, and the 10uH inductor model used above is SDFL2012S100KTF.
The rated current is not as large as the current value recommended by Noridc. 

Unfortunately, these products has in the field, can not change the inductor.

The inductor's datasheet is as below, please help to check, Is there any problem in using this inductor SDFL2012S100KTF？

What is the minimum current requirement for this inductor in nrf52832 DCDC mode?

Using this inductor, we did not find any particular problems, can we continue to use this inductor? Because we have purchased a lot of this inductor.

Looking forward your reply, thank you very much.

SDFL2012S100KTF_Sunlord Inductor.pdf

Best wishes,

Susan

[Bendik Heiskel]

Hi Susan,

Is there any problem in using this inductor SDFL2012S100KTF？

Insufficient inductor current rating will make the inductor saturate and will result in poor efficiency  and noisy operation of the DC-DC converter. The minimum current requirement must be followed for predictable operation of the DC-DC converter.

What is the minimum current requirement for this inductor in nrf52832 DCDC mode?

For the nRF52832 the minimum current rating for the 10uH inductor is 50mA. Using a inductor with higher current rating will result in better efficiency of the DC-DC converter.

Using this inductor, we did not find any particular problems, can we continue to use this inductor?

I would not recommend using this inductor.

 

Best regards,

Bendik

[Susan_cfx]

Hi Bendik,

Thanks for your suggestion. We no longer use that inductor. Are there any risks for products that have already been used in the field? In addition to the low efficiency of DCDC converter. Our product are powered by 1000mAh button cell.

Can we use the LSQEA201212T100K?  attached the datasheet.  

From the graph you can see this inductance is more than 10uH when DC bias is about 50mA, will there be a problem if the inductance is greater than 10uH ?  Thank you in advance.

LSQEA201212T100K.pdf

Best wishes,

Susan

[Bendik Heiskel]

Hi Susan,

Susan_cfx said:

Are there any risks for products that have already been used in the field?

The only other risk is that the DC-DC regulator generate more noise than expected, or irregular operation.

Susan_cfx said:

Can we use the LSQEA201212T100K?

The inductance is right at the 20% accuracy rating that is specified in the reference schematic. This is when only taking the DC bias into account, other factors like temperature may impact the inductance additional.

For reference the inductor used in the nRF52DK is the LBMF1608T100K.

 

Best regards,

Bendik

[Susan_cfx]

Hi Bendik,

OK, we will use this 20% acuracy rating LSQEA201212T100K in production. 

Thanks for your reply.

Best wishes,

Susan