Title :
Ultra-Low-Noise High-Input Impedance Amplifier for Low-Frequency Measurement Applications
Author :
Levinzon, Felix A.
Author_Institution :
Endevco/Meggitt Corp., San Juan Capistrano, CA
Abstract :
The design of a low-frequency high-input-impedance amplifier having probably the lowest noise ever reported is presented. The amplifier´s frequency range is from about 0.07 Hz to about 110 kHz at the -3-dB level. The equivalent input noise voltage spectral density is about 5.6, 1.4, 0.6, and 0.5 nV/radicHz at frequencies 0.1, 1, 10, and 1000 Hz, respectively. Gain of the amplifier is about 83 dB. Noise analysis is made for active-type, capacitive-type, and low impedance signal sources. The contribution from different noise sources in the amplifier and JFET to the overall noise is shown.
Keywords :
junction gate field effect transistors; low noise amplifiers; noise measurement; spectral analysis; JFET; equivalent input noise voltage spectral density; frequency 0.07 Hz to 110 kHz; frequency range; gain 83 dB; low-frequency high-input-impedance amplifier; low-frequency measurement applications; noise analysis; noise figure -3 dB; signal sources; Amplifiers; JFETs; analog circuits; impedance; noise; noise measurement;
Journal_Title :
Circuits and Systems I: Regular Papers, IEEE Transactions on
DOI :
10.1109/TCSI.2008.918213
