The robust low-noise single stage current sensors are available with input inductances from 24 nH to 1.8 µH and a flux noise of 1.2 µPhi0/sqrt(Hz).
An energy resolution of about 100 h makes these devices applicable in almost every system.
The complete gradiometric design results in a parasitic area of only about 1 µm².
Coupling between feedback and input coils is minimized. So, the change in feedback sensitivity with open and shorted input coil is less than 1 %.
The sensors can be cooled in static magnetic fields up to 60 µT without degragation of noise.
Additional positive feedback (APF), bias current feedback (BCF), integrated rf filters, R-C shunts across input coil, and an optional current limiter (Q-spoiler) in series to the input coil make these sensors unique in performance and handling.