DCDC layout on nRF52832

[Francesco_M]

Dear,
I'm designing a PCB with nRF52832 and I will intend to use DCDC converter therefore I putted the two inductors (10uH and 15nH) between DCC and DEC4 pins. The same hardware will be employ also for other applications in which I will use the internal LDO on nRF52832. My question is if I can leave the two inductors mounted on a PCB when I use the internal LDO (obviously when I will use the LDO I will put DCDCEN=0) or if there are some drawbacks or problems with inductors soldered on PCB.

[Andreas]

Hi,

 

With the 10µH and 15 nH inductors between DCC and DEC4 you can use both LDO mode and DCDC mode. There are no drawbacks with using LDO if the inductors are soldered other than increased current consumption.

 

If you do not have the 10µH and 15 nH inductors in place, you should not use DCDC mode, use LDO only. Enabling the DCDC mode without these inductors will brick your nRF.

 

Best regards,

Andreas

[Francesco_M]

Dear Andreas, many thanks for your answer.

I didn't understand If when you wrote "There are no drawbacks with using LDO if the inductors are soldered other than increased current consumption" you refer to extra current consumption due to some leakage or so on in inductors or you refer, in general, to extra current consumption due to LDO mode respect to DCDC mode.
I try to explain better my doubt:

Suppose that we have an application in which there are no high current draws in which LDO mode is convenient respect to DCDC mode but the layout that we use is layout arranged for DCDC (with two inductors mounted). In this case with LDO enabled are there drawbacks? We can leave inductors mounted or it is better desoldered inductors in such a manner to have layout very similar to layout suggested for LDO?

[Andreas]

Hi,

Francesco_M said:

In this case with LDO enabled are there drawbacks?

 No, there are no drawbacks. You can leave the inductors mounted, or you can desolder them, it does not matter to the nRF52. My point was, if you already have the inductors mounted, you might as well use the DCDC mode to save some current, even if current consumption is not too important in the respective application.

 

Best regards,

Andreas