I know that this isn't very sporting, but I honestly can't remember... Rather than spending a long time on worrying about supercaps why not stack two coin cells in series and have a little LDO from 6V to 3V3, the LDO wouldn't be efficient when your running 100mA, but for 1s that wouldn't be much of a problem, the rest of the time your PIC could run efficiently. Better still, you could run the motor straight off the batteries (with PWM) so that they droop, but the LDO & PIC isn't affected. Run the LDO at the lowest possible voltage (2.7V) to minimise the chance of brown out.
There are plenty of tiny LDOs in SOT23-5 footprints etc. if space is a problem. You should really still have bulk capacitance (or at very least put the footprints down for it) -- ╒═════════════════════════════════════════════╕ Andrew Whyte MEng CEng paramita ltd ╘═════════════════════════════════════════════╛ _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user