Patent ID: 7592876

Claim:
A semiconductor device, comprising: a circuit component to perform a function during operation; a reference oscillator circuit to generate a reference signal having a reference frequency, said reference oscillator circuit being unstressed during operation of said circuit component; an aging oscillator circuit to generate an aging signal having an aging frequency that changes over time, said aging oscillator circuit being stressed during operation of the circuit component; and a frequency comparator, coupled to said reference oscillator circuit and said aging oscillator circuit, to compare said aging frequency with said reference frequency to generate an age signal being dependent upon an operational age of said circuit component; wherein said aging oscillator circuit and said reference oscillator circuit includes a leakage oscillator, wherein said reference oscillator circuit and said aging oscillator circuit each comprises an odd number of concatenated stages, the last stage having an output coupled to an input of the first stage, each stage including: a first unit having a leakage component coupled to a reset component at a connection node; a second unit having an inverter, the input of said inverter coupled to said connection node; and a third unit having a gate, a first input of said gate coupled to the output of said inverter, a second input of said gate coupled to an enable signal, and the output of said gate coupled to the output of said stage.