I am not quite certain what the advantages/disadvantages are of using LDV vs DCDC if you are using an external regulator. In my case i use a LiPo battery outputting ~4.2V so i need to drop the voltage down to something 1.8-3.6V for the nRF51822.
Would it be more power efficient to use the LDO @ 1.8V or DCDC at some higher voltage like 2.0V? Either is an option im just not sure since i hear DCDC is more power efficient than LDO.
The DCDC is safe to use with the third revision nRF51 hardware and softdevices S110 8.0.0, S120 2.0.0, S130 1.0.0, S210 5.0.0 or S310 3.0.0. See the nRF51 compatibility matrix to identify third revision…
Also, with DCDC schematics, the DCDC mode is diabled by default?
Yes, the DCDC only works with supply voltages above 2.1V. Therefore you must monitor the status of the supply voltage, either to put the nRF51 into LDO mode when the supply voltage is too low for the DCDC, or gracefully shut the nRF51 down before supply voltage goes below the minimum 1.8V, where the nRF51 will enter brown out reset. You can monitor supply voltage in two ways, with periodically sampling the supply voltage with the internal ADC, or by setting up "power fail comparator" to get an event when the supply voltage goes below a certain threashold, see the nRF51 Series Reference Manual.
The default value of the DCDC register is zero, therefore the DCDC is disabled by default, see the nRF51 Series Reference Manual v3.0, table 61
It seems the latter method is a better way since it's power efficient and more precisely, right?
What about the S110 7.3.0 Soft device? We've received support responses before saying that the DCDC works with that version on Rev3 hardware.
Obviously this contradicts what is said above. Which is correct? Is it just simply the case that the 7.3.0 release was not available at the time of the original answer from Stefan, and it does indeed support the DCDC? Or is it not compatible?