These examples offer a view into what the chip-scale era in timekeeping will look like. The SA.45s CSAC delivers the accuracy and stability of an atomic clock to portable applications for the first time — and does so within those applications’ severe limits on power, size, and weight. It is comparable to other atomic clocks and surpasses OCXOs and TCXOs by wide margins in initial
accuracy and aging.

Portable applications that had to settle for TCXO performance due to power constraints no longer must. Until the CSAC, the lowest-power atomic clock was Microsemi’s own SA.3xm series, with a
steady-state power of 5 W. The SA.45s uses 1/40th of that power. OCXOs offer better performance than TCXOs but are typically in the 1 W–2 W range. That limits their applications to those with large, heavy, and expensive batteries or where mission life is relatively short. Even then, they are a compromise when compared to a true atomic clock like the CSAC.

Then there are size and weight issues, which are always critical in portable applications. The SA.45s is much smaller than any atomic clock (one-third the size of the SA.3xm series, the next smallest), and is generally smaller than the OCXOs that approach its performance. The unit height is especially critical in many applications, and the SA.45s is only 0.45 inches high.

Finally, perhaps the most critical point is availability. The CSAC is not a laboratory prototype. It provides autonomous, reliable operation in production quantities today. That means that when it comes to the next era in atomic timekeeping, the clock is already running.

Read more about Microsemi’s chip scale atomic clocks.

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Tags: Chip Sale Atomic Clock, CSAC, Timing