I am generating semi-pure sine wave voltage signal out of an AVR microcontroller. The thing is I want to amplify this signal (power amplification [voltage and current]) with keeping wave form as source (as it is produced from the AVR pin) considering the best way to do it without damaging the microcontroller And without that much complexity of the circuit to be designed and implemented. The circuit should be supplying about (2500 watt in output [desired output voltage is 220 volts] and the frequency is about 50HZ ) The input is supposed to be varying between (0-5 volts and about 20 milli ampere) I've seen many designs on the web, mostly about RF amplification circuits. I need advice about this certain situation mentioned above. Any help, or reference source or contribution would be appreciated.
Now that you've specified that you want 220 V at 2.5 kW out, it sheds a whole different light on the question. A simple opamp isn't going to do it.
What you want is something called a "inverter". These are devices intended to produce AC power from DC. Note that somehow you still have to supply DC at over 2.5 kW as input, regardless of what topology you use. What the available input voltage is will make a significant difference to the topology.
Another thing to look at are high-power class D amplifiers. At this voltage and power level, inverters and class D amplifiers won't be all that different. Inverters are for a specific known frequency, so can be more targeted to that frequency, whereas class D amplifiers have to handle a range of frequencies.
Either way, messing with this voltage and power level is NOT for beginners. If you have to ask here, you should start with something simpler and less dangerous to learn on. By the time you're ready to take on designing something like this yourself, you won't need to ask here.