Power Matters.™ Precision Commercial of the Shelf ( COTS) Oscillators for Space Applications Peter Cash, Mike Silveira and Matt Stanczyk April 13, 2016 © 2016 Microsemi Corporation

Power Matters.™  Space missions are evolving and now span a wide range of orbits and mission lifetimes that require different methods of mitigation for radiation  Some missions now leverage commercial electronics that allow for state of the art performance at costs appropriate for the programs  Microsemi continues to provide timing for applications such as GPS and SBIRS that require stringent performance, reliability and radiation performance  Microsemi has adapted several products from either military heritage or commercial designs that have adequate radiation tolerances for short duration, CubeSat and low earth orbit (LEO) or experimental missions  The presentation will describe Microsemi’s COTS quartz oscillators and atomic clocks, and the results of radiation testing to 100 krads (Si.) COTs Oscillators for Space - Overview © 2016 Microsemi Corporation.

Power Matters.™ Heritage Approach to Clock Hardening  In the past, frequency sources for space such as crystal oscillators or atomic clocks were developed along the lines of radiation hard by design and testing of components and the clock in its entirety  Such approaches were needed because of long mission durations, beyond 15 years, and complex natural and man-made environments  To maximize the radiation hardness of clocks, common parts were leveraged with definitive radiation responsiveness  Radiation analysis was then utilized to determine the changes in components parameters by the use of statistics, and these results used in Worst Case Circuit Analysis to validate that the clock would operate over the mission.  Finally, radiation testing is performed on hardware as appropriate. Testing included 100% screening and/or radiation qualification testing. © 2016 Microsemi Corporation. Company Proprietary.

Power Matters.™ Alternative Approach  Developing lower cost clocks have two distinct paths  The first path is to substitute commercial parts into an established radiation hardened design.  The second path is to characterize commercial clocks under specific radiation conditions. This is similar to an up-screen approach  To maximize the radiation hardness of clocks, common parts were leveraged with definitive radiation responsiveness  Microsemi is in the process of characterizing three different devices for applications in space An ovenized crystal controlled oscillator, designated the model 9635QT SA45: A ultralow power atomic clock, Chip Scale Atomic Clock or CSAC SA33: A miniaturized atomic clock or MAC © 2016 Microsemi Corporation. Company Proprietary.

Power Matters.™  Based on the heritage designs of the 9600/9700 family of oscillators for which 500+ units are in space  Space design is radiation hardened above 300 krads, along with SEL immunity, neutron insensitivity, SEU acceptable performance  Uses a 3 rd overtone SC cut crystal in a modified Colpitts design and a hybrid circuit for miniaturization  Excellent trade-off for performance and SWaP  Thoroughly analyzed and tested for all environments including radiation  The space version uses established reliability components  The 9635QT uses commercial equivalent parts with the same mechanical construction 9635QT © 2016 Microsemi Corporation. 9635QT Block Diagram

Power Matters.™  Total ionizing dose ( TID) testing was performed on two production oscillators at the University of Massachusetts - Lowell  Satisfactory results for both units with radiation sensitivity of 35 ppb over 100 krads of exposure – equivalent to 3.5e-12 per rad  Performance testing performed before and after testing confirmed the ability of the oscillator to withstand a challenging environment. 9635QT – Radiation Testing © 2016 Microsemi Corporation. 9635QT Radiation Testing

Power Matters.™  Developed under DARPA funding and released to production in 2011  Key performance attributes are performance similar to atomic clocks with extremely low power consumption, < 120 mW.  Use coherent population trapping ( CPT) to interrogate Cesium atoms at 4.6 GHz using a laser diode  Uses commercial electronics from cell phone industry for low power operation and reduced size  Superior frequency accuracy, temperature coefficient and stability compared to crystal oscillators of similar power. CSAC © 2016 Microsemi Corporation. Space CSACPhysics Package Model CSAC Block Diagram

Power Matters.™  Testing was performed in 2013 to determine the capability of the clock to operate under radiation conditions  Three rounds of testing and characterization were conducted  Radiation susceptible component was a commercial TCXO  Candidate radiation tolerant TCXO has been identified and procured  Space CSAC is now capable of meeting a 50 krad environment with the shield shown in the previous page  Details of efforts are provided in PTTI paper in reference 1 CSAC Radiation Testing © 2016 Microsemi Corporation. CSAC TID Testing CSAC Physics Package

Power Matters.™  MAC is a Rubidium atomic clock that uses a more conventional gas cell and leverages CPT technology from CSAC  SWaP is extremely low compared to conventional Rubidium Oscillators ( 2” x 2” x 0.7”, and 5 W steady state power)  Accuracy and stability significantly better than CSAC.  Microsemi delivers its Rubidium oscillators in to many applications, including military environments the have high levels of vibration, shock and thermal variation SA3X - MAC © 2016 Microsemi Corporation. SA3X Rubidium OscillatorSA3X Block Diagram

Power Matters.™  Testing was performed in January 2016 to determine the radiation hardness of MAC.  Configuration did not include any additional shielding or special selection of product  Testing to a level of 10 krad ( Si) exhibited nominal performance  Failure occurred at 12 krad (Si)  Diagnosis confirmed that the failure mode was the TCXO  Plan is to replace device with a radiation tolerant device and repeat the testing  Final version would likely include additional shielding to achieve 30 krad goal SA3X – MAC Radiation Testing © 2016 Microsemi Corporation. SA3X Internal ConstructionSA3X Radiation Testing

Power Matters.™ Radiation Environments  Particular environments are highly dependent on the specific orbits and in turn the mission requirements  Focus of these “radiation capable” devices are cube-sat and LEO missions  9635QT as a result of its simplicity and similarity to space oscillators is most radiation capable  CSAC has been tested for additional environments with excellent results.  CSAC and MAC contain commercial electronics, including FPGAs and micro-processors and are likely to be SEE susceptible and require redundant configuration © 2016 Microsemi Corporation.

Power Matters.™ Comparison of Oscillators © 2016 Microsemi Corporation. 9635QTCSACMACComment Output10 MHz sine wave 10 MHz CMOS 1 PPS 10 MHz CMOS Power Consumption 1.3 W120 mW5 W Steady state 25 degrees C, vacuum Frequency Accuracy 2 x x x 10-11At shipment Temperature Stability ±2 x ±5 x ±2 x to 70 °C Phase Noise  -95 dBc/Hz  -125 dBc/Hz  -145 dBc/Hz  -150 dBc/Hz  -155 dBc/Hz  -50 dBc/Hz  -70 dBc/Hz  -113 dBc/Hz  -128 dBc/Hz  -135 dBc/Hz  -70 dBc/Hz  -87 dBc/Hz  -114 dBc/Hz  -130 dBc/Hz  kHz Aging ( Drift)9 x x10 -10, typical1 x Per month Options 1 PPS Steering, Time of Day

Power Matters.™ Conclusions  Satellite Missions have evolved over the past decade in which trade-offs have been made for duration, reliability, the ability to leverage high performance commercial electronics to achieve performance, price targets and reduced deployment times  High performance clocks can be adapted to support these objectives with minimal compromise for reliability.  Microsemi’s precision clocks the 9635QT, CSAC and MAC are unique products that are capable of meeting these missions. © 2016 Microsemi Corporation.

Power Matters.™ Acknowledgements 1. “Space CSAC: Chip-Scale Atomic Clock for Low Earth Orbit Applications”, M. Stanczyk, P. Cash and Mike Silveira, 2014 PTTI Meeting 2. “SA.3Xm Rubidium Oscillator: Performance and Applications ”,W. Krzewick, P. Gerry and J. Malcolmson, Microsemi, 2016 PTTI Meeting © 2016 Microsemi Corporation. Company Proprietary.