Methods and apparatus for in-situ measurement of mutual inductance between embedded interconnects

A method to determine a mutual inductance between a first communication transmission line and a second communication transmission line, the method comprising:

• providing a periodic coupling current ramp signal to a first communication transmission line that induces a voltage on a nearby second communication transmission line, wherein the voltage is sampled and held on a capacitor;
• integrating the voltage onto a feedback capacitor of a switched capacitor integrator when the charge is positive due to a positive change in voltage of the periodic coupling ramp signal on the first communication transmission line;
• integrating the voltage until the voltage crosses a known threshold as measured on a comparator;
• and
• counting a number of cycles required to cross the known threshold to infer a mutual inductance between the first communication transmission line and the second communication transmission line.

A method to determine a mutual inductance between a first communication line and a second communication line, the method comprising:

• providing a periodic coupling current ramp signal to a first communication transmission line that induces a voltage on a nearby second communication transmission line, wherein the voltage is sampled and held on a first capacitive storage element;
• providing a periodic current pulse signal to the first communication transmission line that capacitively couples a charge onto the nearby second communication transmission line, wherein a non-ideality of the charge that is capacitively coupled is sampled and held on a second capacitive storage element;
• removing the charge that is capacitively coupled from a measurement through a differential switched capacitor integrator;
• integrating the voltage onto a feedback capacitor of the differential switched capacitor integrator when the charge is positive due to a positive change in voltage of the periodic coupling ramp signal on the first communication transmission line;
• integrating the voltage until the voltage crosses a known threshold as measured on a comparator;
• and
• counting a number of cycles required to cross the known threshold to infer a mutual inductance between the first communication transmission line and the second communication transmission line.