Yes, the ds1302 anticipates that with a programmable
resistor to limit inrush.  Its a really nice chip -
same footprint, just add the supercap.  it also
detects the condition of Vbat > Vdd and goes into a
low power mode so it will last longer on backup.

--- Electron <electron2k4@infinito.it> wrote:
> At 22.16 2005.05.12 +0200, you wrote:
> >I'd say the typical thing would be to "independize"
> the supply with a
> >diode and add the supercap. That way you maintain
> power while
> >preventing the supercap from discharging through
> other parts of the
> >circuit:
> >
> >      |\ |
> >+5V---| )|----+-------------------+
> >      |/ |    |                   |VCC
> >              |+              +-------+
> >            ----- SUPERCAP    |  RTC  |
> >            -----             +-------+
> >              |                   |GND
> >GND-----------+-------------------+
> >
> >Something like that should work. I think.
> 
> Depending on the supercap's ESR, I would add a serie
> resistor to it.
> Inrush current can be very high for a very long time
> otherwise. :D
> 
> 
>  
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