Voltage rail monitoring to detect electromigration

A field replaceable unit (FRU), wherein the FRU is a field replaceable board for an electronic device, and wherein the FRU comprises:

• an integrated circuit that comprises:
• a target voltage rail, wherein the target voltage rail provides power to at least one circuit node in the integrated circuit;
• an isolation power switch, wherein the isolation power switch selectively connects the target voltage rail to a power source;
• a voltage sensor that couples the target voltage rail to a reference voltage source;
• a memory supervisor coupled to the voltage sensor;
• a voltage memory coupled to the memory supervisor, wherein the voltage memory stores a record of an initial voltage decay rate for the target voltage rail while isolated from a manufacturer's power source;
• a clock coupled to the memory supervisor, wherein the clock triggers the memory supervisor to take serial voltage readings from the voltage sensor while the target voltage rail is isolated from a field power source to create a field voltage decay rate for the target voltage rail;
• a voltage record comparator logic, wherein the voltage record comparator logic compares the initial voltage decay rate to the field voltage decay rate for the target voltage rail;
• and
• an output device coupled to the voltage record comparator logic, wherein the output device indicates that a difference between the initial voltage decay rate and the field voltage decay rate for the target voltage rail exceeds a predefined limit, and wherein the difference between the initial voltage decay rate and the field voltage decay rate for the target voltage rail is a result of current leakage caused by electromigration in the integrated circuit.

A computer program product for detecting electromigration in a field replaceable unit, the computer program product comprising a non-transitory computer readable storage medium having program code embodied therewith, the program code readable and executable by a processor to perform a method comprising:

• quiescenting an integrated circuit that is within a field replaceable unit (FRU), wherein the FRU is a field replaceable board in an electronic device;
• applying, via an isolation power switch, a test voltage from a field power source to a target voltage rail in the integrated circuit, wherein the test voltage is below an operational voltage for transistors within the integrated circuit;
• isolating, via the isolation power switch, the target voltage rail from the field power source;
• measuring, by a voltage sensor coupled to the target voltage rail, a field voltage decay rate for the target voltage rail, wherein the voltage sensor couples the target voltage rail to a reference voltage source;
• comparing, via a voltage record comparator logic within the integrated circuit, the field voltage decay rate to an initial voltage decay rate for the target voltage rail;
• and
• in response to a difference between the field voltage decay rate and the initial voltage decay rate for the target voltage rail exceeding a predetermined limit, sending, via the voltage record comparator logic, a signal to an alarm on the FRU, wherein the difference between the initial voltage decay rate and the field voltage decay rate for the target voltage rail has been predetermined to be a result of current leakage caused by electromigration in the integrated circuit.