The input offset voltage of the op-amp is also multiplied by the gain of 1000. Because the attenuation of the voltage divider is approximately the same as the inverting gain the output should be inverted and have about the same amplitude as the input from AWG CH-A. To insure that the amplifier output is the correct amplitude and not clipped, use the ALICE Oscilloscope tool to measure the signal in the time domain.
Set the frequency of AWG channel A to 250 Hz. Set the Min value to 1.5 V and the Max value to 3.5 V. When feedback is provided, as in an inverting amplifier, the gain is given by G = –R 2/R 1 however, it must be recognized that the magnitude of this gain can never exceed the gain as given by the gain-bandwidth product. The gain can be specified as a simple number (magnitude) or in dB.įigure 1, from the OP97 datasheet, graphically illustrates this relationship. G f is defined as the gain-bandwidth product, GBW, and for all input frequencies this product is constant and equal to fc. This is also the Closed-Loop Bandwidth or the maximum frequency when the feedback is configured with a closed loop gain of 1. For the OP97 op-amp, the unity gain frequency is 900 KHz, the open-loop gain at this frequency is simply one. At low frequency the gain is maximum, decreases linearly with increasing frequency, and has a value of one at the frequency commonly referred to as the unity gain or cut-off frequency F cf (in equation form, G fc = 1). This gain is ideally infinite at all frequencies, but in a real op-amp is finite, and depends on the frequency. The forward gain, G is defined as the gain of the op-amp when a signal is fed differentially into the amplifier with no negative feedback applied.