Amplifying a 2.5V Square wave coming from a microcontroller?

There's no work to be done, I'm not even sure why he drew up the opamp circuit he doesn't need a linear amplifier, he just needs to drive a power transistor from the square wave he already has. I doubt he even has a 2.5V square wave, it's probably a 5 volt square wave at 50% duty cycle and he's reading it on a multi meter expecting the results to be acurate. He should feed the micro controller output into a mosfet driver and use a simple push/pull mosfet pair to drive the square wave from whatever voltage source he wants.