[time-nuts] Ultra low power RTC

Attila Kinali attila at kinali.ch
Wed Mar 7 11:03:38 EST 2018


On Wed, 7 Mar 2018 08:27:00 -0500
Bob kb8tq <kb8tq at n1k.org> wrote:

> Since we don’t often *need* the smallest cell made *and* we’re probably 
> talking lifetime of the cell….. does 22 na vs 33 na matter?

Not really. It starts to matter when you are space limited and don't
have space for a CR2032.

At this level, though, every tiny bit of leakage matters. Finger prints,
dust, humidity, FR4... Going below 1µA in current consumption is like
going below 10^-12 in frequency stability, suddenly 1M is a low resistance.
 
> Based on the previous data on the chip, I think I would just run the crystal
> all the time. 

The the watches (quartz with analog dials) I have run >5 years
on their batteries, an I am pretty sure they don't have a CR2032.
And at least one of them must have a TCXO.


			Attila Kinali
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
                 -- Miss Matheson, The Diamond Age, Neil Stephenson


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