The maximum power dissipation of the TL084CDR is 670mW at 25°C free-air temperature, and it decreases as the temperature increases.
Yes, the TL084CDR is rated for operation from -40°C to 125°C, but the maximum junction temperature is 150°C. Be sure to derate the power dissipation accordingly.
To ensure stability, make sure to decouple the power supply pins with 0.1uF capacitors, use a gain of 5 or greater, and avoid capacitive loads greater than 100pF.
The input impedance of the TL084CDR is typically 2MΩ, but it can vary depending on the specific application and operating conditions.
While the TL084CDR can be used as a comparator, it's not the best choice due to its relatively slow slew rate and limited output current. Consider using a dedicated comparator IC instead.