Recommend DC-DC inductor component selection for custom nRF52832 Board PCB design?

[vishal]

Hello sir,

I have completed PCB design of custom nRF52832 board. Can i use following component instead of recommended part No in reference design. I have also mentioned mft part no that will be use. Because this recommended part number is not available early.

want to use recommended mft part no. L1= 3.9nH(36401E3N9ATDF) <---------- L1(LQP15MN3N9B02D) L2=10uH(LBMF1608T100K ) <---------- L2(LBMF1608T100K) L3=15nH(744784115A) <---------- L3(HK100515NJ-T)

And also is it ok to use Meander type Antenna Groundedtrance-15.2mm.

So sir please check this above inductor part number specification and let me know its ok to use in my hardware design. Please sir give me reply asap for purchase this inductor component.

Thanks........

[Jørn]

You have posted the same serial number for both L2 inductors. Is this a typo?

[vishal]

Ya its my mistake sorry, I correct this L2 10uH i want use following mft part number. L2=10uH(LBR2012T100KL2 ) <---------- L2(LBMF1608T100K) In this LBR2012T100KL2 only change is footprint package 0805(2012 metric) and DC current rating is 150mA so can use this in my design. And also is it any problem if DC current rating is 150mA for 10uH inductor.

[Jørn]

Hello Vishal

L3: The characteristics of these seem to be close to identical, and I doubt it will cause a problem

L2: According to the nRF52832 datasheet the inductor needs to have at least 50 mA maximum current. The inductor in our design is rated for 80 mA, so going up in value should not be a problem. I don't believe the package-size matters too much as from what I understand it will mainly deal with low frequency currents. Larger package sizes in components will alter their parasitics, which again can affect filter characteristics. The higher frequency the larger the effect will be.

L1: The tolerance of the inductor you have chosen is slightly worse than the one in the reference design. This can slightly alter the filter characteristics of the matching network, and can cause a slight mismatch, which again can affect your range.

Meander antenna is fine to use, but they can be tricky to design. The antenna performance is highly dependent on layout and any physical object in proximity of it. A good ground plane is important to ensure stable operation. Unfortunately we do not have any guidelines for meander antennas, and it is very difficult to judge the performance of the antenna based on images. I would recommend you make a prototype and measure the performance of the antenna. Be sure to facilitate for antenna tuning and a matching network in your prototype.

Best regards

Jørn Frøysa

[Sweety]

What should be the minimum rated current of inductor L1?

[vishal]

Thanks Jorn for your suggestion, so for this three inductor can you recommend to me other mft part number instead of in reference design. Because this same part number is not available quickly. If you recommend we will use only for testing PCB and prototype after that in final production we will use same inductor part number as per in reference design. So sir plz recommended me other inductor but in same specification.