\node[op amp, yscale=-1,scale=0.8] (op) at (0,0) {};

\draw (op.out) to [short,*-] (op.out|-op.north)
               to [short, -] ++ (0,-0.2) coordinate (x)
               to [short, -] (x-|op.-)
               to [short, -] (op.-);

\draw (op.+) to [short, -] ++ (-1,0) coordinate (y)
             to [R,l_=$R_{\mathrm{2}}$] ++ (0,-2)
             node[sground,scale=0.7] {};

\draw (y) to [C,l_=$C_{\mathrm{2}}$,*-*] ++ (-2,0) coordinate (x);
\draw (x) to [C,l_=$C_{\mathrm{1}}$,*-o] ++ (-2,0) coordinate (in)
          node[anchor=east] {I};

\draw (x) to [short, -] ++ (0,1)  coordinate (im)   
          to [R,l=$C_{\mathrm{1}}$] (im-|op.out)
          to [short,- ] (op.out)
          to [short,-o] ++ (0.5,0)
          node[anchor=west] {O};

\node[anchor=north] at (x) {X};
\node[anchor=south] at (y) {Y};