The MA25401A Atomic Clock Frequency Reference has short-term stability (Allan Deviation) of 3.0e–10 @ t = 1 sec, typical long-term aging of <9e–10 per month, and maximum frequency change of ±5e–10 over an operating temperature range of –10 °C to 55 °C. The MA25401A 10 MHz output may be used to synchronize the internal frequency reference to an external reference clock to within 5 ppb accuracy. A USB C interface is used for power.