A low noise chip scale atomic clock, the LN CSAC 090-01921-000, is now available commercially from Microsemi. The latest addition to Microsemi's Quantum family of atomic clocks, the LN CSAC enhances the low size, weight, and power (SWaP) of existing CSACs by adding low phase noise performance, critical in many radar and communication applications for military and industrial sectors. Combining the atomic clock accuracy of OCXO and the standard CSAC technologies, the device employs an ultra-low power crystal oscillator within the control loop of the atomic clock to optimize Allan deviation (improves to less than 2E-11 at 1 second) and phase noise (-87 decibels relative to the carrier per hertz (dBc/Hz) at a 1 Hz offset and a noise floor of -155 dBc). With its low power consumption (240 mW) the device becomes ideal for portable applications requiring precise synchronization and time keeping, especially in GPS-denied environments. The LN CSAC produces two outputs, a 10MHz sine wave and 1PPS, in a CMOS 0 to 3.3 V format. It also accepts a 1PPS input for synchronization and provides an RS-232 interface for monitoring and control. The LN CSAC, model number 090-01921-000, is available now.