Analysis and development of the high frequency common-mode rejection of an instrumentation amplifier

This investigation involves the development and analysis of an instrumentation amplifier in the mid-band and high frequency regions. The common-mode gain of a simple difference amplifier configuration is analyzed in detail to find the limitations due to nonideal properties of an op-amp. Compensation methods are then described.

SPICE analysis is used extensively throughout the thesis to confirm the hand calculations. Experimental data is presented showing good agreement between the calculated and measured common-mode gain. A common-mode gain less than -100 dB is achieved for frequencies up to 50 kHz utilizing low-cost LF 351 op-amp.