A metallic leadframe for use with a semiconductor chip intended for
operation in a changing magnetic field comprises a chip mount pad having
at least one slit penetrating the whole thickness of the pad and
substantially traversing the area of the pad from one edge to the opposite
edge. This slit is wide enough to interrupt electron flow in the pad
plane, but not wide enough to significantly reduce thermal conduction in a
direction normal to the pad plane, whereby the slit is operable to disrupt
eddy currents induced in the pad by the changing magnetic field.
A semiconductor device intended for operation in a changing magnetic field,
comprising a leadframe with a chip mount pad having at least one slit in a
configuration operable to suppress eddy currents induced in the pad by the
changing magnetic field; an integrated circuit chip, having an active and
a passive surface; the passive surface attached to the mount pad by a
polymeric material; and the active surface having a Hall structure
including current and voltage terminals integrated into the circuit,
whereby the changing magnetic field can be measured without diminution by
said eddy currents.
