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

In this paper, a dc current source dedicated to four-probe low-frequency noise measurements is presented. An output impedance value of 3 M Omega with a maximum output current of 1.5 mA was achieved. The white noise level of the current source was measured to be 4 x 10(-23) A(2) . Hz(-1) with a corner frequency of 30 Hz. Thanks to its quasi-ideal behavior in terms of noise level and high output impedance value, this current source can be used to measure the intrinsic noise of materials using four-point measurements without any experimental or analytical corrections.