In special-purpose op-amp design, an instrumentation amplifier is characterized by extremely high input impedance, excellent common-mode rejection, and substantial gain. Choose the best trio that correctly completes the statement.

Introduction / Context:Instrumentation amplifiers are precision differential amplifiers used for sensor interfacing, biomedical measurements, and industrial data acquisition. They excel at amplifying tiny differential signals in the presence of large common-mode voltages and noise. This question checks whether you know the core performance trio that defines an instrumentation amplifier.

Given Data / Assumptions:

• The device is an instrumentation amplifier (not a general-purpose op-amp stage).
• Typical application involves small sensor signals with potentially high source impedance.
• Common-mode voltages and interference may be significant.

Concept / Approach:Three hallmarks define instrumentation amplifiers: very high input impedance to prevent sensor loading, very high common-mode rejection ratio (CMRR) to suppress unwanted voltages common to both inputs, and high, accurate gain that is usually set by a single resistor. These traits enable low-level signal extraction with minimal distortion.

Step-by-Step Solution:

Verification / Alternative check:Datasheets for classic instrumentation amplifiers (e.g., 3-op-amp INA topology) emphasize Zin in megaohms to gigaohms, CMRR often > 100 dB, and gains from 1 to thousands via one resistor, confirming this trio.

Why Other Options Are Wrong:Noise factor, grounding, power: important system issues, but not the defining trio.

Working voltages, current capacity, output impedance: not the figure-of-merit set for instrumentation amplifiers.

Output gain, output loading, power: vague and incomplete for precision instrumentation needs.

Common Pitfalls:Confusing general op-amp specs with instrumentation-grade metrics. Overlooking that CMRR is the key measure for common-mode suppression, not just “noise.”

Final Answer:input impedance, common-mode rejection, gain