LTC1799 actually evaluates current and voltage at its input and simulates RC evaluation. I used it for converting voltage into frequency ( temperature stability wasn't crucial then ).
...probably LTC1799 and similar chips have been overlooked
here. They are so small, inexpensive, nice things.
They convert resistance into frequency using their own
precise capacitor inside and the wonder is that the
resistor being measured is at constant voltage. The
temperature accuracy is...