Operational Amplifier Fundamentals Unit 2 – The Inverting Amplifier
Exercise 3 – Inverting Amplifier Response
EXERCISE OBJECTIVE
When you have completed this exercise, you will be able to relate the gain and bandwidth of an
op amp inverting amplifier. You will measure bandwidth with an oscilloscope.
EXERCISE DISCUSSION
- Gain-bandwidth product and slew rate are op amp parameters that affect the operation of an
inverting amplifier. - Gain-bandwidth (GBW) is an op amp parameter that does not depend on op amp
configuration. - Gain multiplied by circuit bandwidth equals the GBW of an op amp.
- The GBW product is also called the unity-gain bandwidth since GBW is specified at a gain
of one. - A general plot shows that bandwidth (B or bw) and gain are inversely proportional.
- Bandwidth decreases as gain increases.
- Bandwidth = GBW product/circuit gain
- The LF441 op amp has a specified GBW of 1 MHz (at unity gain).
- The bandwidth of an inverting amplifier is reduced by placing a capacitor across the
feedback. - As frequency increases, capacitive reactance decreases. At a specific frequency, capacitive
reactance equals RF. This frequency is called the breakpoint frequency. - At the breakpoint frequency, an output signal drops 3 dB.