Frequency References & Oscillators Paul R. Gerry Senior Product Manager, Clocks BU Paul.Gerry@microsemi.com
Agenda Frequency & Time Atomic Clock Technology Components Clock Portfolio Miniature Atomic Clock (MAC) Chip Scale Atomic Clock (CSAC) Low Noise CSAC (LN CSAC) Microsemi Systems Clocks Portfolio Cesium Technology and Products Rubidium Clocks Masers
What is Frequency Frequency = the number of cycles per second Frequency measurements begin with the sine wave. An ideal sine wave is a very clean signal (no noise), but it’s never really achieved. When we look a frequency reference we need to characterize and analyze the amount of noise on that signal. Frequency = the number of cycles per second Ideal frequency source generates a pure, repeatable sine wave
What is Frequency Stability & Accuracy Courtesy John Vig
Atomic Clock Technologies Rubidium Gas Cell: 6,834,682,610.904 Hz Cesium Beam: 9,192,631,770 Hz Hydrogen Maser: 1,420,405,751.768 Hz Fountains use cesium, rubidium Stored Ions use mercury, ytterbium Optical Clocks use mercury, calcium The resonant frequency of atoms does not age… the apparatus to interrogate or confine atoms can in some atomic clocks
Atomic (Passive) Clock Basics Synthesizer must translate from oscillator frequency to atomic frequency; very easy with today’s direct digital synthesis techniques Gas cell rubidium clocks (to be described) do not run at this frequency Stimulate an energy state change in the atoms Detect when resonant frequency is achieved Servo the oscillator to maintain optimal performance
Component Clocks
Industry Leader in atomic clock technology Microsemi Component Clocks Portfolio Rubidium Clocks GPSDO’s CSAC Industry Leader in atomic clock technology
Component Clocks Positioning Spec\Type XPRO High-Performance Rubidium SA.22C Precision Rubidium Oscillator SA.35m Miniature Atomic Clock Quantum™ Chip Scale Atomic Clock (CSAC) Dimensions (cm) 12.7 x 9.2 x 3.9 7.82 x 11.2 x 2.31 5.1 x 5.1 x 1.8 1.6 x 1.39 x 0.45 Volume 456 cm3 203 cm3 < 47 cm3 < 17 cm3 Power @25° C 13 W 10 W 5 W <120 mW ADEV @ 1 sec < 1E-11 <3E-11 <3E-11 <2.5E-10 Differentiator Highest Performance Legacy Telecom Performance Good SWaP Best SWaP Microsemi’s atomic clocks meet a variety of application needs
Performance Versus Power & Size 1-Sec ADEV Monthly Aging Rate Product Power @25°C Volume ≤1E-11 < 1E-11 13 W 456 cm3 ≤3E-11 5E-11 10 W 203 cm3 1E-10 5 W 47 cm3 ≤2.5E-10 3E-10 120 mW 17 cm3 XPRO SA.22c Performance Power Consumption, Size SA.3Xm CSAC
QuantumTM MAC Product Overview
The QUANTUM™ Miniature Atomic Clock (MAC) The QUANTUM™ SA.3Xm Miniature Atomic Clocks bring the accuracy and stability of an atomic clock with all the benefits of Size, Weight and Power. Key Specifications ±5.0E-11 accuracy at shipment <1.0E-10 month aging rate 5 W Power Consumption 47 cc in Volume
The QUANTUM™ Miniature Atomic Clock (MAC) SA.3Xm Miniature Atomic Clock (MAC) is the world’s first commercial Coherent Population Trapping atomic clock Cost effective and easily adaptable to a wide variety of timing and synchronization applications. Three versions to address a wide range of performance and price points – SA.31m, SA.33m, SA.35m Small Size Similar size to an OCXO Compact design 51 x 51 x 18 mm (2.0 x 2.0 x 0.7 in) Low Weight Less that 85 g (3 oz) Low Power - Lower power consumption than traditional Rb clocks 5 W @ 25°C(14 W max during warm-up)
The QUANTUM™ Miniature Atomic Clock (MAC) Competitive performance: Wide operating temperature range Superior temperature coefficient. ONLY Rb clock with laser-based (not lamp-based) source; so no frequency “hops & pops” associated with lamp-based clocks
Microsemi MAC Clock Comparison Product SA.35m SA.33m SA.31m Size (volume) 46cm3 / 2.8in3 Power @25°C 5W Phase Noise (1Hz / 10Hz / 100Hz / 1kHz / 10kHz) <-70 dBc/Hz <-87 dBc/Hz <-114 dBc/Hz <-130 dBc/Hz <-140 dBc/Hz <-65 dBc/Hz <-85 dBc/Hz <-112 dBc/Hz Aging (monthly) <±1.0E-10 <±3.0E-10 TempCo (-10C - 75C) <1E-10 <1.5E-10 <1E-9 Allan deviation (t=1s, 10s, 100s) <3E-11 <1.6E-11 <8E-12 <5E-11 <2.5E-11 <1E-11
MAC Applications
Target Applications & Markets Precision Frequency Reference Hold-over Key Application(s) Mobile Infrastructure X 1 – 1.5 uS/24 hr holdover Wired Communications Holdover/Internal reference Military/Defense Aerospace Internal reference Research/Medical Instrumentation & Timing MACs Synchronize things with no physical connections including applications such as Providing Longer holdover - such as when base station loses its connection to a timing signal Providing precise frequency as free running frequency source – such as 10 MHz reference for test and measurement equipment
Example Application: Frequency Reference Test equipment producers seek to make lower power smaller size equipment Spectrum analyzers have had significant reductions in power 200 W to 110 W and significant reductions in size MAC Traditional Rubidium Location Internal External Size Smaller Larger Power 5 W @ 25ºC ~10W : ~2X MAC Heat Less More Fans None or smaller size Fans required Cabling No cables External cabling Accuracy (10 MHz) <0.0005 Hz Mounting Configuration PCB Mount Large Mechanical
Example Application: ATE Synchronization
Example Application: Mobile Base Station Synchronization Frequency Phase / Time CDMA2000 50 ppb Should +/-3µs, shall +/-10µs GSM N/A UMTS/ W-CDMA Femtocells 250 ppb TD-SCDMA +/- 1.5µs LTE (FDD) LTE (TDD) +/- 1.5µs small cell, +/- 5µs large cell LTE MBSFN +/- 1-32µs, implementation dependent LTE-A CoMP (Network MIMO) +/- 500 ns (0.5 µs), pre-standard WiMAX (TDD) 2 ppm absolute, ~50 ppb between base stations +/-1 - 8 µs, implementation dependent GSM, UMTS, LTE Network Interface 16 ppb, suggested to meet 50ppb RF specification New phase sync requirements – more exacting than before Carriers demanding assurance & reliability through variety of solutions
Typical SA.3Xm (MAC) Rubidium Holdover
MAC Technology Overview
MAC – Technology Overview The MAC uses Coherent Population Trapping (CPT) Coherent Population Trapping (CPT) interrogation of Rubidium Laser diode (VCSEL) modulated to achieve CPT resonance Photodiode detects the CPT resonance Jinquan Deng, Peter Vlitas, Dwayne Taylor, Larry Perletz, and Robert Lutwak, "A COMMERCIAL CPT RUBIDIUM CLOCK“ EFTF 2008 Toulouse, France. 10 MHz VCXO synthesizes 3.4 GHZ microwaves Microwave frequency is locked to CPT resonance signal stabilizing the output to 10 MHZ
MAC Assembly – Full Exploded View Cover Assembly Shield 1 2 Spacer Resonator Assembly Rubidium Cell Assembly 1 Resonator Assembly Electronics PCBA 2 Laser Block Assembly Shield Laser Block Assembly Baseplate I/O Pins
CPT versus Lamp-based Simplified Lamp Based Rubidium Clock Model Simplified CPT Based Rubidium Clock Model
MAC Developers Kit 10 MHz CMOS Output Analog Tuning Input 10 MHz Sine Output 15 VDC Power Input RS232 Connector Lock Indicator Power On Indicator
MAC Developer’s Kit SA.3Xm is ordered separately The developer’s kit contains Universal input power supply CD-ROM with software, user’s guide and sample software to control the MAC Heat sink Thermal pad MAC mounting hardware Part Number: 090-44300-00
Microsemi’s Rubidium Clock Lineup XPRO Traditional lamp-based Rubidium atomic clock Our highest-performance clock SA.22c Traditional lamp-based Rubidium atomic clock Legacy clock aimed at telecom applications. Not recommended for new applications, as will eventually be replaced by MAC enhancements.
QuantumTM CSAC Product Overview
Today’s CSAC Product Lineup SA.45s Chip Scale Atomic Clock The smallest, lowest-power atomic clock on earth. Key specs: < 120 mW power consumption < 17 cc in volume LN CSAC Combines the accuracy of the chip scale atomic clock with the spectral purity of an OCXO in a compact size requiring low input power Key specs: < 250 mW power consumption < 47 cc in volume -87 dBc/Hz @ 1 Hz phase noise
The QUANTUM™ Chip Scale Atomic Clock (CSAC) The QUANTUM™ SA.45s Chip Scale Atomic Clock brings the accuracy and stability of an atomic clock with all the benefits of Size, Weight and Power. Key Specifications ±5.0 x 10-11 accuracy at shipment <3.0x 10-10/month aging rate <120 mW Power Consumption <17 cc in Volume
CSAC Work Technology Overview
Miniaturizing the Physics Package US Patent #7215213 Tensioned polyimide suspension Microfabricated silicon vapor cell Low-power Vertical-Cavity Surface Emitting Laser (VCSEL) Vacuum-packaged to eliminate convection/conduction with an overall demonstrated thermal resistance of 4000° C/W Entire physics package can operate on 15 mW@25° C
How the CSAC is Made Suspensions Resonance Cell Stack-up Vacuum Seal Spin-on polyimide over Silicon Photodefine polyimide and lift-off Metallization on polyimide Backside etch to release Resonance Cell DRIE holes in silicon Load cesium and buffer gas Anodic bond windows Stack-up Bond VCSEL/Photodiode to suspensions Stack up and epoxy on pick-and-place machine Vacuum Seal Bake-out and activate getter in lid before braze Frame Spacer Lid Photodiode Cell Spacer Lower Suspension VCSEL LCC Upper Suspension Resonance Cell
Completed CSAC Physics Package Physics Package in LCC Before Sealing
CSAC Developer’s Kit Evaluation Board 3.3 VDC Replaceable Fuse Lock Indicator Power-On Indicator Analog Tuning Input BITE 10 MHz Output 1 PPS Output 1 PPS Input Power Switch 5 VDC Power Input
CSAC Developer’s Kit - Details Kit contents Evaluation board with socket for CSAC* Mounting hardware to hold evaluation board Wall socket power supply to provide power to evaluation board RS-232 cable to connect PC to evaluation board CD-ROM with User’s Guide, sample software to control the CSAC Microsemi Ordering P/N 990-00123-000 * CSAC unit not included as part of kit
The QUANTUM™ Low Noise Chip Scale Atomic Clock (LN CSAC) brings the accuracy and stability of an atomic clock with all the benefits of Size, Weight and Power. Key Specifications ±5.0 x 10-11 accuracy at shipment <3.0x 10-10/month aging rate <250mW Power Consumption <47 cc in Volume <-87 dBc/Hz @ 1 Hz
CSAC vs LN CSAC Product CSAC LN CSAC Size (volume) 40.6 x 35.3 x 11.3 mm ( <17 cc) 51 x 51 x 18 mm (47 cc ) Power @25°C (Warm-up) 120mW (140 mW) 250mW (775mW) Phase Noise 1Hz 10Hz 100Hz 1kHz 10kHz <-50 dBc/Hz <-70 dBc/Hz <-113 dBc/Hz <-128 dBc/Hz <-135dBc/Hz <-87 dBc/Hz <-120 dBc/Hz <-140 dBc/Hz <-145 dBc/Hz <-150 dBc/Hz Aging (monthly) +3E-10 TempCo +5E-10 Allan deviation (t=1s, 10s, 100s, 1000s) 2.5E-10 8E-11 2.5E-11 8E-12 2E-11 5E-11 Output 3.3V CMOS 10 MHz Sine Supply Voltage 3.3 V +0.1
LN CSAC Developer’s Kit Power LED Replaceable Fuse LN CSAC Not Used Power Switch RS232 10 MHz Sine Output Lock BITE LED 1 PPS Output Lock BITE 1 PPS In
LN CSAC Developer’s Kit - Details Kit contents The Developer’s Kit includes: Description Part Number Evaluation Board 089-00794-000 Power Adapter 140-00041-000 RS232 Cable 060-00322-000 Introduction Doc 689-02461-000 Microsemi Ordering P/N 990-00565-000 * CSAC unit not included as part of kit
LN CSAC Developer’s Kit Details 10 MHz Out (SMA) – The LN CSAC output is a sine wave output capable of delivering up to 9 dBm into a 50 ohm load. Replaceable Fuse – Replacement fuse: Littelfuse Part No. 0453 01.5 5 VDC Input – Input power to the evaluation board is provided on a 5 mm (center positive) coaxial connector (PS1). RS232 Connection (DB9M) –The evaluation board provides a level shifter (U3) which converts the LN CSAC 0-3.3 VDC serial interface into the RS232 standard +/-12 for a direct interface with a PC COM port. Lock BITE LED – Indicates normal operation following the initial acquisition of the clock signal. Lock BITE (SMA ) – Buffered output of the LN CSAC Power Switch – Controls power to the board Power LED – Indicates the state of the power switch 1 PPS Input (SMA) – accepts an 1 PPS input (logic high: 2V < Vin < 20V) and generates a 0 to 3.3V CMOS pulse to the LN CSAC 1 PPS Output (SMA) - 1 PPS out is buffered by a 0 to 3.3 V Logic Gate
Applications that benefit from the QUANTUM SA.45s CSAC
What Applications Benefit from the CSAC? Application performance needs Precise time for synchronization without direct connection Ability to hold precise time in absence of GPS Minimize Size, Weight, and Power (SWaP) Example Applications that benefit from CSAC : Portable “man-pack” equipment for the military Underground or underwater distributed geophysical sensors Enhanced Military GPS Receiver IED Dismounted Jammers Tactical UAVs CSAC fulfills all of the above needs
CSAC Opportunities Dismounted Military Radios (Backpack) Use TCXO’s, OCXO’s today Sometimes too much drift for GPS-denied scenarios Problem will get worse with new, higher-bandwidth waveforms Excellent fit for SA.45s CSAC as these new waveforms get rolled out Marine Geophysical Sensors Oscillators inside underwater geophysical sensors must provide highly accurate timing without GPS access. The CSAC’s superior aging rate and low power consumption compared to crystal oscillators mean sensors can deliver more accurate data for longer periods or conversely, with smaller, less expensive batteries <120mW power consumption (Option 001) <3.0E-10 monthly aging rate <17 cc in volume 35 g in weight TempCo +5E-10 (Option 001) Enhanced Military GPS Receivers Direct Y Acquisition after extended outage 3 SV navigation GPS Tracking loop improvements A/J Improvements CSAC Calibration
CSAC Opportunities Tactical UAV’s IED Dismounted Jammers (Backpack) Payloads are always stretched on Size, Weight, and Power “SWaP” SA.45s CSAC helps in all three areas! < 17 cc, 35 g, < 125 mW CSAC provides excellent holdover performance in GPS-denied environments IED Dismounted Jammers (Backpack) Ultra-low power consumption plus high stability make the SA.45s CSAC ideal for IED jammers small enough and light enough to be carried by soldiers. High stability allows jammers to be highly synchronized, so friendly force communications won’t be blocked <125mW power consumption (Option 002) <17 cc in volume 35 g in weight σy <5E-12 T = 1 hour Portable Test Equipment Internal Atomic Clock option for the ultimate in handheld frequency accuracy The atomic clock inside provides for a durable, handheld instrument that delivers high accuracy necessary to prove regulatory compliance. The internal atomic clock module eliminates loose cables and potential snag hazards from external references
Systems Clocks
Microsemi Systems Clocks Portfolio Cesium Hydrogen Maser Cs4000 AOG 110 5071A CsIII MHM 2010 Microsemi is viewed as the market leader worldwide Rubidium Instrument Quartz Instrument 8200 8040C 4145C 1000C
Cesium Technology Applications Cesium Technology is considered the most comprehensive holdover option against GNSS vulnerabilities Exhibit no frequency drift Maintains 5x10-15 accuracy over the life of the instrument Critical for long-term autonomous operation No on-going calibration required More expensive than Rubidium and OCXO Consumes more power and space Typical applications Fixed wireline communications infrastructure Under sea (Submarine) Satellite ground stations Metrology and Time Keeping 5071A CsIII
Cesium Applications Clock stability enables: Precision navigation Secure communications backbone Better realization of UTC Ground Stations Secure comm Navigation command, control, communications, computers, intelligence, surveillance, and reconnaissance Autonomous operation. No GPS. Timing holdover Timekeeping Metrology
Cesium Positioning Price Feature/Performance TimeCesium 4400/4500 Standard Performance Telecom Environment 5071A High Performance Full featured Price Cs4000 Standard Performance Full featured Custom’s platform CsIII – entry level cesium used in applications where minimal outputs are required and size is an issue Cs4000 multiple RF outputs, specials platform can be configured with or without front panel. Ethernet interface and touch panel display provide unmatched user interface for local and remote access 5071A high performance instrument with unmatched long term stability. Is viewed as the instrument of choice for high performance applications, especially in the timekeeping community CsIII (4310B) Standard Performance Entry level Feature/Performance
Microsemi Cesium Beam Tube Clocks CsIII CS4000 Accuracy (Std/high) 1E-12/5E-13 1E-12/N/A Stability Floor (Std/Hi) Typical High Performance 5E-14/1E-14 5E-15 5E-14/N/A RF outputs 5MHz 10MHz 1MHz 1kHz 100kHz 10MHz TTL 1 2 Pulse Output 3 Phase Noise (1Hz) -106dBc -95dBc Power AC/DC/Batt AC/DC Temp Range 0 to 50ºC Front Panel Control Std N/A Management RS-232
Rubidium Gas Cell Frequency Standards Most widely used type of atomic clock Smallest, lightest, lowest power Least complex, least expensive, longest life Excellent performance, stability & reliability Device of choice when better stability is needed compared to crystal oscillator Lower aging, lower temperature sensitivity Faster warm-up, excellent retrace Used as an inexpensive holdover technology
Rubidium Applications Clock stability enables: Higher resolution measurements in ATE systems Fast frequency hopping radios to maintain sync Precision time difference of arrival measurements Longer operation without GNSS Ground Stations OEM Test Equipment SIGINT command, control, communications, computers, intelligence, surveillance, and reconnaissance Autonomous operation. No GPS. Timing holdover ATE Test Ranges Tactical Data link
Rubidium Product Line 8040C - Rubidium instruments ATE systems Ground stations General purpose reference Ground benign environment 8200 – Military Rubidium modules Electronic warfare Secure communications Environmental extremes
8040C Standard Configuration
8200 Key Features Low profile package Rugged design Hermetic package 4.0”x4.63”x0.95”H Rugged design Shock tested to 50g Vibration tested to 15g Hermetic package Impervious to altitude, salt fog, humidity -40C to +80C operating temp range Inputs: 22 to 32Vdc Outputs: (1) 10 MHz Monitoring and control: Serial Port: RS232 TTL Indicators: Lock, Analog 8200 not controlled by ITAR No export license required
8200/8200LN Specifications 8200 SSB Phase Noise 10 MHz 1 Hz < - 72 dBC/Hz 10 Hz < - 90 dBC/Hz 100 Hz < -128 dBC/Hz 1 KHz < -140 dBC/Hz 10 KHz < -148 dBC/Hz Spectral Purity Harmonics < - 50 dBC Non-Harmonics < - 70 dBC (<150 MHz) < - 80 dBc (>150 MHz)
8200/8200LN Specifications 8200 Short Term Stability (ADEV) 1 S Aging (after 1 month) Monthly < +5.0E-11 @ + 25C Frequency accuracy at shipment
MHM 2010 – Industry’s Leading Hydrogen Maser Most stable atomic clock Longest life atomic clock Installed base of more than 130 masers Clock of choice at key metrology and radio astronomy labs The Symmetricom maser, originally know as “Sigma Tau”, has a design legacy which goes back to NASA hydrogen masers. The performance and long life of these masers is carried forward in today’s Symmetricom designs.
Maser Key Applications Metrology Where? International timekeeping laboratories Why a Maser? Maser provides superior frequency stability out to one week. This stability is the key attribute of a maser in a timescale application as well as support to today’s primary standard’s research Radio Astronomy VLBI – Very Long Baseline Interferometry VLBA – Very Large Baseline Arrays Maser offers the frequency stability required to allow multiple VLBA stations to operate as a single instrument To provide the precise timing references required to allow the VLBA stations to operate as a single instrument, a hydrogen maser system is used. This hydrogen maser, which also serves as a frequency reference for the receiving systems. The maser allows "time stamp" and frequency information to be included in the data recorded on a removable hard disk drive. Hard disks are shipped from the stations to the VLBA correlator at the end of a coordinated observation. The VLBA correlator receives data from a bank of disk drives. Disk drives from all the VLBA stations, plus as many as ten additional observatories may be played back simultaneously, and through the precise "time tags" and frequency information placed on the disk by the hydrogen maser at each site, the observation is essentially re-created for the correlator. This allows an effective dish antenna diameter equivalent to the distance between the most distant observatories in the array. Typically thousands of miles.
MHM 2010 Stability and Environmental Allan deviation (measured in 0.5Hz bandwidth): Standard Low Phase Noise Option 1s 1.5E-13 8.0E-14 10s 2.0E-14 1.5E-14 100s 5.0E-15 4.0E-15 1,000s 2.0E-15 10,000s 1.5E-15 Floor* <1.0E-15 Typical Long term <2.0E-16 per day* Auto tuning: no external reference required * Typically achieved after extended period of unperturbed, continuous operation. Temperature variation: ±0.25°C, Relative humidity: ±10% ENVIRONMENTAL • Temperature sensitivity: <1.0E-14/°C • Magnetic sensitivity: <3.0E-14/Gauss • Power source sensitivity: <1.0E-14
MHM 2010 Phase Noise Standard phase noise Low phase noise option 5MHz -116dBc -110dBc -90dBc 10Hz -135dBc -129dBc -109dBc 100Hz -148dBc -142dBc -122dBc 1kHz -155dBc -149dBc 10kHz 100kHz Low phase noise option 5MHz 10MHz 100MHz 1Hz -130dBc -124dBc -102dBc 10Hz -150dBc -138dBc -117dBc 100Hz -158dBc -146dBc -126dBc 1kHz -160dBc -133dBc 10kHz -153dBc -134dBc 100kHz
1000C: Ultra High Performance Crystal Oscillator Microsemi’s improved Ultra High Performance Crystal Oscillator 1000C provides state-of-the-art short term stability and phase noise! 1000C Specs High Performance Ultra High Performance Frequency (Outputs) 5 MHz (4) Phase Noise (dBc) 1 Hz 10 Hz 100 Hz 1 kHz 10 kHz 100 kHz -120 -145 -156 -160 -130 -150 -157 ADEV 0.1s -> 100s <3E-13 <2E13 1000C
1000C:Ultra High Performance Crystal Oscillator Serves customers in Defense and Metrology market applications MW synthesizers, Microgravity meters, VLBI, satellite ground station Radio and missile ranging timing systems Deep space communications Satellite command terminals GPS monitoring stations
4145C Ultra-Clean Phase-Locked Oscillator Ultra-clean phase-locked oscillator filters the output from a high performance Cesium frequency standard Improves the Phase Noise and Allan Deviation (short term stability) Low broadband phase noise Ultra high short and mid-term stability performance Cost effective way to improve phase noise and Allan deviation of a PRS Ease of set up with Cesium standards Applications Radio and missile range timing systems Deep space communications, satellite command terminals, GPS monitoring stations
Thank You Ramki Ramakrishnan Director of Marketing & Business Dev, Clocks BU ramki.ramakrishnan@microsemi.com +1 707-636-1914 Paul R. Gerry Senior Product Manager, Clocks BU Paul.Gerry@microsemi.com +1 978-522-5798 Steve Fossi VP and General Manager, Clocks BU Steve.Fossi@microsemi.com +1 707-636-1810