Single JFET Front-End Amplifier for Low Frequency Noise Measurements with Cross Correlation-Based Gain Calibration

We propose an open loop voltage amplifier topology based on a single JFET front-end for the realization of very low noise voltage amplifiers to be used in the field of low frequency noise measurements. With respect to amplifiers based on differential input stages, a single transistor stage has, among others, the advantage of a lower background noise. Unfortunately, an open loop approach, while simplifying the realization, has the disadvantage that because of the dispersions in the characteristics of the active device, it cannot ensure that a well-defined gain be obtained by design. To address this issue, we propose to add two simple operational amplifier-based auxiliary amplifiers with known gain as part of the measurement chain and employ cross correlation for the calibration of the gain of the main amplifier. With proper data elaboration, gain calibration and actual measurements can be carried out at the same time. By using the approach we propose, we have been able to design a low noise amplifier relying on a simplified hardware and with background noise as low as 6 nV/√Hz at 200 mHz, 1.7 nV/√Hz at 1 Hz, 0.7 nV/√Hz at 10 Hz, and less than 0.6 nV/√Hz at frequencies above 100 Hz.

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DEDICATED INSTRUMENTATION FOR HIGH SENSITIVITY, LOW FREQUENCY NOISE MEASUREMENT SYSTEMS

Fluctuation and Noise Letters ◽

10.1142/s0219477504001963 ◽

2004 ◽

Vol 04 (02) ◽

pp. L385-L402 ◽

Cited By ~ 23

Author(s):

C. CIOFI ◽

G. GIUSI ◽

G. SCANDURRA ◽

B. NERI

Keyword(s):

Background Noise ◽

Flicker Noise ◽

Low Frequency ◽

High Sensitivity ◽

Design Guidelines ◽

Low Noise ◽

Frequency Noise ◽

Low Frequency Noise ◽

Low Frequencies ◽

Noise Measurements

Low Frequency Noise Measurements (LFNM) can be used as very sensitive tool for the characterization of the quality and the reliability of electron devices. However, especially in those cases in which the frequency range of interest extends below 1 Hz, instrumentation with an acceptable low level of background noise is not easily found on the market. In fact, at very low frequencies, the flicker noise introduced by the electronic components which make up the instrumentation becomes predominant and several interesting phenomena which could be detected by means of LFNM may result completely hidden in the background noise. This consideration is not limited to the case of input preamplifiers but does extend to any piece of instrumentation that contributes to the LFNM systems, and in particular to the power supplies used for biasing the Device Under Test. During the last few years, our research groups have been strongly involved in the design of very low noise instrumentation for application in the field of LFNM. In this work we report the main results which we have obtained together with a discussion of the design guidelines that have allowed us, in a few cases, to reach noise levels not to be equalled by any instrumentation available on the market.

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LOW-FREQUENCY NOISE MEASUREMENTS OF IR PHOTODETECTORS WITH VOLTAGE CROSS CORRELATION SYSTEM

Measurement ◽

10.1016/j.measurement.2021.109867 ◽

2021 ◽

pp. 109867

Author(s):

Krzysztof ACHTENBERG ◽

Janusz MIKOŁAJCZYK ◽

Carmine CIOFI ◽

Graziella SCANDURRA ◽

Krystian MICHALCZEWSKI ◽

...

Keyword(s):

Cross Correlation ◽

Low Frequency ◽

Frequency Noise ◽

Low Frequency Noise ◽

Ir Photodetectors ◽

Noise Measurements ◽

Correlation System

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Ultra low-noise preamplifier for low-frequency noise measurements in electron devices

IEEE Transactions on Instrumentation and Measurement ◽

10.1109/19.69939 ◽

1991 ◽

Vol 40 (1) ◽

pp. 2-6 ◽

Cited By ~ 55

Author(s):

B. Neri ◽

B. Pellegrini ◽

R. Saletti

Keyword(s):

Low Frequency ◽

Low Noise ◽

Frequency Noise ◽

Low Frequency Noise ◽

Noise Measurements ◽

Electron Devices ◽

Ultra Low Noise ◽

Low Noise Preamplifier

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A Low-Noise and Quasi-Ideal DC Current Source Dedicated to Four-Probe Low-Frequency Noise Measurements

IEEE Transactions on Instrumentation and Measurement ◽

10.1109/tim.2019.2890891 ◽

2020 ◽

Vol 69 (1) ◽

pp. 194-200 ◽

Cited By ~ 4

Author(s):

Jean-Marc Routoure ◽

Sheng Wu ◽

Carlo Barone ◽

Laurence Mechin ◽

Bruno Guillet

Keyword(s):

Current Source ◽

Low Frequency ◽

Low Noise ◽

Frequency Noise ◽

Low Frequency Noise ◽

Noise Measurements ◽

Dc Current

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A Low-Noise Chopper Amplifier with Offset and Low-Frequency Noise Compensation DC Servo Loop

Electronics ◽

10.3390/electronics9111797 ◽

2020 ◽

Vol 9 (11) ◽

pp. 1797

Author(s):

Yuekai Liu ◽

Zhijun Zhou ◽

Yixin Zhou ◽

Wenyuan Li ◽

Zhigong Wang

Keyword(s):

Frequency Band ◽

Low Frequency ◽

Low Noise ◽

Frequency Noise ◽

Low Frequency Noise ◽

Neural Signals ◽

Noise Compensation ◽

Front End ◽

Servo Loop ◽

Chopper Amplifier

The low-frequency and low-amplitude characteristics of neural signals poses challenges to neural signals recording. A low noise amplifier (LNA) plays an important role in the recording front-end. A chopper-stabilized analog front-end amplifier (FEA) for neural signal acquisition is presented in this paper. It solves the noise and offset interference caused by the servo loop in the chopper amplifier structure. The proposed FEA employs a switched-capacitor (SC) integrator with offset and low-frequency noise compensation. Moreover, a dc-blocking impedance is placed for ripple-rejection (RR), and a positive feedback loop is employed to increase input impedance. The proposed circuit is design in a 0.18-µm 1.8-V CMOS process. It achieves a bandwidth of up to 9 kHz for local field potential and action potential signals acquisition. The referred-to-input (RTI) noise is 0.72 µVrms in the 1 Hz~200 Hz frequency band and 3.46 µVrms in the 200 Hz~5 kHz frequency band. The noise effect factor is 0.43 (1 Hz~200 Hz) and 2.08 (200 Hz~5 kHz). CMRR higher than 87 dB and PSRR higher than 85 dB are achieved in the entire pass-band. It consumes a power of 3.96 µW/channel and occupies an area of 0.244 mm2/channel.

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