The maximum power dissipation of the LM324AMX is 670mW, which is calculated based on the package thermal resistance and the maximum junction temperature.
While the LM324AMX can be used as a comparator, it's not the best choice due to its relatively slow slew rate and limited bandwidth. A dedicated comparator like the LM339 or LM2901 would be a better option.
To ensure stability, make sure to add a compensation capacitor between the output and the inverting input, and adjust the gain and bandwidth of the amplifier to prevent oscillations.
The input impedance of the LM324AMX is typically around 2MΩ, but it can vary depending on the specific application and operating conditions.
The LM324AMX is rated for operation up to 125°C, but its performance may degrade at high temperatures. Be sure to check the datasheet for temperature-related specifications and consider using a more temperature-stable op-amp if necessary.