Low‐noise preamplifier with input and feedback transformers for low source resistance sensors

J. Lepaisant, M. Lam Chok Sing, D. Bloyet
1992 Review of Scientific Instruments  
We describe the design, schematics, and performances of a very-low-noise, low-frequency preamplifier. It operates in the 5 Hz-100 kHz range and offers an input equivalent voltage noise density as low as 65 pV/ ,/I%; the current noise increases with frequency and settles to about 1.5 pA/ @ at 100 kHz. The amplifier uses input and feedback signal transformers and operates in full differential mode; a -163 dB common-mode rejection ratio is achieved at line frequency. Design methodology is applicable to other ranges of frequencies.
doi:10.1063/1.1143171 fatcat:zyvlx2actbguhjrlyl6rjhdagu