An integrated circuit includes a sub-system and a reference sub-system. The reference sub-system is substantially identical to the sub-system but is non-operating by default. The integrated circuit includes a test circuit that obtains a parameter value of the sub-system and a reference parameter from the reference sub-system. The integrated circuit detects deterioration of the sub-system based on the parameter value and the reference parameter. The integrated circuit deactivates the sub-system and activates the reference sub-system responsive to detecting deterioration of the sub-system.