OP07 Integrator in Dual Slope Capacitance Converter Slowly Saturates—Why?

I am using Op-Amp OP07 to implement an integrator as part of a dual slope capacitance digital converter circuit. My problem is that the feedback capacitor is slowly charging to saturation. The input resistance is a switched capacitance type. I have not used any compensation in this. Checked with various values of capacitances. The result is same except that the charging time is different. Can you suggest a solution?

Hi,

The rate at which the output voltage increases (the rate of change) is determined by the value of the resistor and the capacitor, “RC time constant“. Its either changing the capacitor or the resistor. To avoid saturation, you can put a resistor in parallel with the integrator capacitor to limit the low frequency gain.

You can read this for more information: "Linear Integrated Circuits("")":https://books.google.com.ph/books?id=rvvMkSM7O84C&pg=PA205&lpg=PA205&dq=avoid+capacitor+saturation+integrator+circuit&source=bl&ots=Tobt9oiWIR&sig=tIKYw3ZPe4xbH1vU3flZgDzptx0&hl=en&sa=X&ei=2uaZVfOJGsetmAWoy4OQBg&ved=0CBwQ6AEwAA#v=onepage&q=avoid

What is the capacitor dielectric,
cheers,
Richard