LM4250 Amplify circuit problem.

I want to amplify a square signal, whose amplitude is 400 mv, and frequency is 200 khz.  And I used the LM4250, the circuit diagram is shown below:

I connect the square signal to the positive input, and connect v- to the ground.  I connect the pin 8(Quiescent Current Set) to a 1M ohm resistor.  And V+ connects to 5 v.  However, there is no output voltage and signal at all(detect with oscilloscope).  However, when I change the AC input signal to DC signal(input voltage is 1 v), keep other setting the same, and I could detect the output voltage is equal to 4.5 v.  So I don't know what is wrong with my circuit and how to solve this problem?  And does this pin 8 necessary and do I need to connect pin 8 to any resistor?

Thanks very much.