We propose an inverting closed-loop amplifier architecture providing high input impedance and a theoretically zero gain error, without requiring infinitely large loop gain. The architecture is based on two nested amplifiers closed in feedback through a resistive network. A straightforward CMOS implementation is also given. Simulations using a 0.35-mum CMOS process are found in agreement with expected results. Monte Carlo simulations have also shown the robustness of the proposed approach against process tolerances