First I would suggest running the PIC at low speed,
assuming you can do this, like run at 32kHz or even
10kHz when it is running.

Instead of sleep mode, I think you could use something
like this: (crazy one-transistor circuit follows)

(only uses 0.5uA when off, and self-turns on)

 +6v -------*-------------------*-----------------------
            |                   |
            Ca 0.1uF            |  PNP beta>500
            |                   E
            *-----*---*-------B
            |     |   |         C--------*-----------,
            |     |   |                  |           |
            |     |   |                  |+Pwr       |
            |     C   R 1M          ,-----------,    |
            |     |   |             |           |    |
            Ra    |   |             |           |    Cp 1uF?
        10M |     '---*-------------|x   PIC    |    |
            |   0.33uF        _on   |           |    |
            |                       |           |    |
            |                       '-----------'    |
            |                            |           |
 Gnd -------*----------------------------*-----------*---


When the circuit is off, the only current is through
Ra, about 0.5uA. When Ca charges enough, PNP turns on,
and although only about 150uA? goes to the load the
main cap Cp will charge ok. PIC starts up, (about 80uA?)
and first thing it does is pull pin x low, turns on
circuit hard for relaible running.
To turn the circuit off, the PIC simply makes pin x
active HI, discharging Ca very quickly and turning
everything off.

Yep I know it's rough, but I think with some fiddling
it could be made to work quite well. :o)
-Roman



Morgan Olsson wrote:

> If you can arrange to run on the 32kHz xtal all times except the rare occasion every month that would help much!
>
> >        But I forgot to say, that the system will use 2 button cell (lithium)
> >batteries in parallel,
> >so Vdd is 6volt, and will use a 4mhz Xtal, cause it has to download data
> >every 1 month.
> >        Another thing, is that I have never been able to get a lower consumption
> >that 0.08 ma @5v,
> >in sleep mode !!!
> >        So, what can I do ?

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