Wide bandwidth transimpedance amplifier for extremely high sensitivity continuous measurements

Area of Science:

• Electronics
• Instrumentation
• Biophysics

Background:

• Accurate current measurements are crucial for analyzing nanodevices and biomolecules.
• Existing transimpedance amplifiers often face limitations in measurement time and bandwidth.
• High sensitivity is required for detecting small leakage currents in various experimental setups.

Purpose of the Study:

• To present a novel wide bandwidth transimpedance amplifier design.
• To enable unlimited measurement durations by addressing standing current discharge.
• To achieve high signal amplification across a broad frequency range.

Main Methods:

• The amplifier integrates integrator and differentiator stages with a feedback loop for current discharge.
• It utilizes a configuration that maintains amplification over the full bandwidth.
• The design ensures a rail-to-rail dynamic range for sinusoidal current signals.

Main Results:

• A flat frequency response from 0.6 Hz to 1.4 MHz was achieved.
• The amplifier successfully operates with device under test (DUT) leakage currents up to tens of nanoamperes.
• Independent of DUT leakage current, a rail-to-rail dynamic range for sinusoidal signals was demonstrated.

Conclusions:

• The developed transimpedance amplifier provides a robust solution for high-sensitivity current measurements.
• Its wide bandwidth and continuous operation make it ideal for noise spectral and impedance analysis.
• The circuit is well-suited for applications in nanodevice characterization, biomolecule studies, and scanning probe microscopy.