$R_2=180 \Omega$, 
\begin{equation}
\frac{1}{I_{\mathrm{OUT}}} \frac{\partial I_{\mathrm{OUT}}}{\partial T} \simeq 3300 \times 10^{-6}-1500 \times 10^{-6}=1800 \mathrm{ppm} /{ }^{\circ} \mathrm{C}
\end{equation}