@Gus, thanks.  Worth a try.

@Russell, thanks.  Yes, it a bistable design; 1.25V or 5.5V.  I agree,
it does seem naughty, and it is good to get these second opinions.

@Brent, thanks.  Yes, the device is standalone powered from a tiny
solar cell taken from a garden light, average 0.5 mA to the PIC,
around 3.5 mA from the battery, so the specified divider will be
significant.

Using the divider as it is, disconnecting the op-amp and rerouting the
feedback directly to the switcher shows about 1V of switching noise on
the 5.5V output.  But it does now start every time!  Yay.

http://dev.laptop.org/~quozl/DS1Z_QuickPrint37.png (upper trace is
Vout, lower trace is 47 uH inductor).

My plan is to remove the op-amp, change to use the specified divider
(lower half being 4k7) and increase the solar cells to balance the
power budget.

--=20
James Cameron
http://quozl.netrek.org/
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