Abstract: A circuit and method automatically compensate a monolithic integrated Hall sensor having a Hall element therein, wherein a device for generating operating currents is technologically and thermally tightly coupled with the Hall element. The production-induced and temperature-induced variations in the sensitivity of the Hall element are compensated for by a defined control of the supply current and the offset current. For the control, the thermal and technological parameters of the Hall element semiconductor region or equivalent regions in corresponding circuits are used. For this purpose, at least two current sources are provided which generate at least two auxiliary currents with different temperature dependences. By means of adding/subtracting devices, resultant currents with other temperature dependences are formed from the auxiliary currents by summation/subtraction and different weighting.

Abstract: A frequency mixing circuit is provided which comprises first and second differential pairs each formed of two transistors different in emitter area from each other and constant current sources for respectively driving the first and second differential pairs. The collectors of the transistors having a large emitter area of K (K>1) and the collectors of the transistors having a small emitter area of 1 of the first and second differential pairs are respectively connected in common. Between the both differential pairs, the bases of the transistors having a emitter area of K and the bases of the transistors having a emitter area of 1 are respectively connected in common. A first AC signal to be mixed is applied to one of two sets of the commonly connected bases and a second AC signal to be mixed is applied to the other thereof. Thus, the degradation of NF can be reduced and a good high frequency characteristic can be obtained at a low current.