EMC Sensitivity Analysis of Crystal Oscillator through Direct Power Injection (DPI)

Crystal oscillators, owing to their high-stability output, usually act as the primary clock of a system PLL. To ensure that the PLL output clock remains robust, the oscillator-generated clock should maintain a stable frequency. This makes it crucial to ensure that connections to the off-chip crystal unit are immune to EMC noise. This work presents a simulation methodology for Direct Power Injection for checking EMC robustness of crystal oscillators used in systems on chip. The analysis has been done on NXP's microcontroller devices. Simulation and experimental results have been presented along with recommendations for improving the EMC robustness of crystal oscillators.