A versatile timing microsystem based on wafer-level packaged XTAL/BAW resonators with sub-µw RTC mode and programmable HF clocks

This paper introduces and demonstrates with high yield a novel concept for the packaging under vacuum of tuning fork quartz XTALs on top of a silicon interposer equipped with TSVs. It paves the way to the implementation of a monolithic timing microsystem where the ASIC is part of the housing of a newly designed tiny 131-kHz XTAL to reach extreme module miniaturization (1.5,*,1.1,*,0.7 mm3) and integrity. As this task is still ongoing, an early demonstration of the generic versatile timing module is presented using a chip-on-board approach with standalone conventionally packaged XTAL and BAW resonators. The module achieves 0.4 µW power dissipation and pm 2 ppm stability over {-} 40 circ C to 85 circ C in RTC mode and can deliver on-demand programmable clocks between 1-50 MHz. The latter are obtained either with a RC PLL or after division of the signal obtained from a 2-GHz BAW DCO at a power dissipation of 100 µ W and 5.3 mW, respectively