Miniature atomic clocks currently achieve the high level of frequency stability, required for today communication systems and localization devices. Thanks to the combination of a dedicated application specific integrated circuit (ASIC) with a microcontroller and a MEMS atomic vapor cell-based physics package on a single PCB, a small, low power and highly integrated solution is reported. This clock demonstrates a mid-term stability on par with commercial products based on discrete electronics. This article focusses on the prototype built around the proprietary ASIC such as the general firmware architecture, the thermal loops, and the CPT frequency lock loop. The result for different CPT tracking hardware and algorithm are presented.
