An integrated fluxgate device has a magnetic core on a control circuit. The magnetic core has a volume and internal structure sufficient to have low magnetic noise and low non-linearity. A stress control structure is disposed proximate to the magnetic core. An excitation winding, a sense winding and a compensation winding are disposed around the magnetic core. An excitation circuit disposed in the control circuit is coupled to the excitation winding, configured to provide current at high frequency to the excitation winding sufficient to generate a saturating magnetic field in the magnetic core during each cycle at the high frequency. An isolation structure is disposed between the magnetic core and the windings, sufficient to enable operation of the excitation winding and the sense winding at the high frequency at low power.