Reliability assessment of CMOS differential cross-coupled LC oscillators and a novel on chip self-healing approach against aging phenomena

摘要

In this paper, reliability of CMOS differential cross-coupled LC oscillators is examined, and a novel on chip aging detection and healing technique is developed to increase the lifetime of oscillator circuits. Aging causes degradation in several transistor parameters, such as threshold voltage, mobility, and transcon-ductance. While these changes cause irregular timing characteristics and increased power consumption in digital circuits, the case is quite different for their analog counterparts. Analog circuits, especially nonlinear ones, show more deviations at the output due to parameter changes. In order to evaluate the aging effects on nonlinear analog circuits, two different oscillator structures (n-type and p-type) with 5 GHz oscillation frequency were designed using 0.13 μm technology. The phase noise analysis of fresh and aged oscillators was performed analytically and through simulations. Based on these analyses the robustness of oscillators was discussed. Finally, an on chip aging sensor and self recovery mechanism are proposed to increase the robustness of the CMOS LC oscillators.