Differential Transimpedance Amplifier Circuit for Correlated Differential Amplification

Case ID:

Researchers at the University of Arizona have created a differential transimpedance amplifier circuit for correlated differential amplification. The amplifier circuit increases electronic signal-to-noise ratio in charge detection circuits designed for the detection of very small quantities of electrical charge and/or very weak electromagnetic waves. A differential, integrating capacitive transimpedance amplifier integrated circuit comprising capacitor feedback loops performs time-correlated subtraction of noise.


When sensitive detectors are employed, their extreme sensitivity makes them sensitive to environmental factors that can produce undesirable electronic noise that obscures the true signal. Examples of such environmental factors include: interfering electromagnetic waves, thermally-induced effects such as, thermally induced dark current, circuit and instrumental operating conditions, background radiation, and other random noise sources. When such noise due to environmental factors is present, its amplification can produce a total signal that is dominated by noise contributions rather than by the true signal that one desires to measure.


  • Higher detection sensitivity for weak signals
  • Less need for electromagnetic shielding


  • Detection schemes for detection of ions, electrons, and other charged particles are especially susceptible to such environmental noise problems
  • Ion detectors are required in analytical instrumentation such as ion mobility spectrometers (IMS), ion mobility-based explosive and chemical-warfare-agent detectors, and mass spectrometers
  • Other applications of this invention are applicable to sensitive detection means for photodiodes, phototransistors, light detection arrays, and CMOS light detectors

Status: issued U.S. patent #7,403,065

Patent Information:
Contact For More Information:
Jonathan Larson
Senior Licensing Manager, College of Science
The University of Arizona
Lead Inventor(s):
M Denton
Roger Sperline
Christopher Gresham