Gain vs. Bandwidth and Current Feedback Operational Amplifiers

In this lab we will demonstrate the inverse relationship between closed-loop gain and bandwidth in conventional operational amplifiers, then experiment with a different type of operational amplifier whose gain and bandwidth are independent of each other (the current feedback amplifier). The amplifier which we will use is the Burr Brown Model OPA658, which is designed for low gain (1 to 5 inverting or non-inverting), wide bandwidth (200+ MHz) applications.

In working with high-speed op amps, it is necessary that your circuit be neatly constructed to minimize stray capacitances, that a single, short ground bus be used, and that the supply voltages be bypassed at the op amp.

A. Conventional Op Amps

B. Current Feedback Op Amps

NOTE: The supply voltages for the OPA658 op amps CANNOT exceed +- 5.5 volts, and typically operate off of +- 5 volts. Adjust your breadboard voltage to +- 5 or slightly lower volts before going further.

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