Expected current consumption differs from product spec

[bootchk]

In the readme of this repository, in a table it says: System ON, no RAM retention: nrf51: 1.4uA

But in the nrf51822 product spec v3.3 on page 47 it says: ION,16k SYSTEM-ON base current with 16k RAM enabled: 2.6uA typical

It seems to me these are the same case, but the values differ.

One explanation is that the readme shows measured values for one test, which might not be typical. Or are the values in the readme supposed to correspond with the product spec?

AFAIK, this case has two RAM blocks enabled (using current in both SYSTEM ON active and SYSTEM ON sleep states) but for all blocks RAM retention is disabled (contents lost in SYSTEM OFF state.) Disabling a block (say clearing bit 0 of RAMON register) removes power from the RAM block in SYSTEM ON mode, while enabling RAM retention (say setting bit 16 of RAMON register) keeps power on to the RAM block while in SYSTEM OFF mode. It makes no sense to disable a RAM block (it's power in SYSTEM ON) and also enable RAM retention. RAM retention only is meaningful if the RAM block is also enabled (for power in SYSTEM ON mode.)

I suppose the 1.4uA value could be for one block (8K) RAM enabled? It makes no sense to disable all the RAM, since the system at least needs a stack.

Maybe I misunderstand something.