Safely driving a SG90 servo with AVR PWM
The servo has independent power supply lines and control line



The high motor current travels through the power supply wires (black/red), while the orange wire is just a high impedance input that goes to the internal control circuit.

You can drive the control wire directly from an AVR I/O without a problem.



In case you are interested about the internal circuit of the SG90 servo, you can see it here



The internal controller is AA51880 and the orange wire drives pin 14 of the IC.