Options
2007
Conference Paper
Titel
Spinning current offset in vertical Hall sensors caused by imperfect wiring
Abstract
Using the spinning current (SC) technique in vertical Hall sensors is well known, but the existing literature on this topic normally neglects the wire-caused impedances. In this paper we will show that even tiny asymmetries in the arrangement of the wiring might cause a spinning current offset (offset after application of the spinning current method) of several mT. Another often neglected reason for offset after spinning current is the junction field-effect of the Hall device. Because of this nonlinearity, mismatching impedances in the wiring produce a further SC offset. Measurements and simulations clearly show that it is of fundamental importance for spinning current operation that the wires match exactly. Mismatching 'feedline' resistors create SC offset only in combination with mismatched Hall resistors or mismatched 'cross-arrangement' resistors. However, that is normally the case. Mismatching 'cross-arrangement' resistors create SC offset, even if the nonlinear Hall resistors match perfectly. Additionally they create rather more SC offset than the 'feed line' resistors. If the wiring does not match, then the spinning current technique cannot work efficiently. Taking into account the wire caused-impedances and the junction field-effect gives a very good indication to sensor layout requiring small SC offset values.
Konferenz