Investigation of speed sensors accuracy for process and aging compensation

Process, Voltage, Temperature and Aging variations have become an important issue for advanced technology nodes and thus very accurate speed sensors have become necessity for adaptive compensation schemes. This paper presents experimental results of different speed sensors that can be used for process and aging compensation. Replica of critical path in ring oscillator and a dedicated design of a sub-set functional critical path are compared with regard to microprocessor speed for reference. Measurements and simulations are performed on large sample sets for varied range of temperatures. Accuracy of speed compared to reference circuit to be monitored is discussed.