Switching node regulator for sfp ethernet adaptor. A method is disclosed for regulating voltage on an integrated circuit formed on a substrate to power circuitry on the substrate. An unregulated power supply is provided as an input to the integrated circuit connected between a positive node and a reference node on the integrated circuit. Current is sourced in a first current sourcing step through drive circuitry on the substrate from the positive node to an inductor/capacitor reactive circuit external to the integrated circuit. The output of the inductor/capacitor reactive circuit comprises a filtered regulated power supply voltage that is operable to power at least a portion of the circuitry on the substrate. Current is sourced in a second current sourcing step through the drive circuitry on the substrate from the reference node to the inductor/capacitor reactive circuit when the current in the inductor is ramping down. A controller is operable to control the first and second sourcing steps to alternately source current to the inductor/capacitor reactive circuit from the positive and reference nodes. The controller is further operable to prevent substantially any current from being drawn through the substrate body during either the first current sourcing step or the second current sourcing step and delivered to the inductor/capacitor reactive circuit during ramp up or ramp down of the current in the inductor/capacitor reactive circuit and during any transition there between.