MOSA Open Architectures

Military control room, computer and soldier at desk, typing code and tech for communication army office.

Modular open systems approach (MOSA) is a strategic US DoD initiative to reduce system cost by improving the integration of systems provided by different manufacturers, increase interoperability, and speed technology refresh. Such open architecture systems rely heavily on precise timing and synchronization across various systems and technologies to ensure mission success. And precise timing must be maintained in the toughest conditions of military operations.

SiTime Endura™ ruggedized MEMS timing solutions are specifically designed for aerospace and defense applications. Without the inherent weakness of quartz timing, all-silicon Endura products deliver the performance and robustness required for open architecture applications such as radial clock cards.

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SiTime Endura Ruggedized Timing Benefits

Robust in Harsh Conditions

< ±1E-9 OCXO stability over -40 to 95°C

Ultra-Low vibration sensitivity <1E-11/g

High shock survivability >30,000 g

Better Performance

<1 µsec time error after 24-hr holdover

<5E-12 ADEV from 1 to 1000 s

<170 dBc/Hz low phase noise

Ease of Design

Low SWAP solutions

Low sensitivity to power supply noise

Easy to integrate into plug-in cards

Precision Timing in Open System Architectures

SiTime Endura™ ruggedized COTS MEMS oscillators, TCXOs and OCXOs are a low SWaP solution with extremely low sensitivity to vibration and shock and address the wide range of applications in MOSA/SOSA/CMOSS compliant systems.

SiTime innovation in MEMS timing technology delivers oscillators with advanced temperature compensation: Endura Super-TCXO^® are rated with frequency stability as low as ±5 ppb over -40 to 95°C and are used to replace quartz OCXO with the benefits of small package, lower power, higher reliability, and robustness.

SiTime new Low Phase Noise Super TCXO^® combines low frequency stability of ±100 ppb over -40 to 105°C with low g-sensitivity of 0.01 ppb/g and low phase noise competitive in most RF applications: they simplify RF receiver architecture and can replace also replace an OCXO.

MEMS Timing Solutions for Open Architectures

Devices	Better Performance	Key Features
OCXOs SiT7111 10 to 60 MHz SiT7112 60 to 220 MHz SiT7101 10 to 60 MHz SiT7102 60 to 220 MHz	Stability over temperature: ±1E-9, ±3E-9, ±5E-9 Allan deviation: 5E-12, 1 s to 100 s g-sensitivity: 1E-11/g Daily aging: <1E-10 daily aging Low phase noise fc=10 MHz: -91 dBc/Hz (1 Hz), -145 dBc/Hz (1 kHz), -175 dBc/Hz (100 kHz)	Temperature range: -40°C to 95°C Package (mm): 9.0 x 7.0 x 3.6 420 mW steady-state power I2C and SPI frequency pull option LVCMOS or Clipped Sine 3.3 V supply voltage
Ultra-low Stability Super-TCXOs SiT5543 1 to 60 MHz SiT5541 1 to 60 MHz	Stability over temperature: ±5E-9, ±10E-9, ±20E-9 g-sensitivity: 1E-11/g total gamma Allan deviation: 1.5E-11, 1 s to 10 s 20-year aging; 150 ppb	Temperature range: -40°C to 95°C, -40°C to 105°C Package (mm): 7.0 x 5.0 CER Voltage control or I2C frequency pull option LVCMOS or Clipped Sine 2.5 V, 3.3 V supply voltage
Low Phase Noise Super-TCXOs SiT7201 10 to 60 MHz SiT7202 60 to 220 MHz	Stability over temperature: ±100 ppb to ±250 ppb g-sensitivity: 0.01 ppb/g total gamma Low phase noise fc=10 MHz: -91 dBc/Hz (1 Hz), -152 dBc/Hz (1 kHz), -175 dBc/Hz (100 kHz) Allan deviation: 1E-11, 1 s to 10 s	Temperature range: -40°C to 105°C Package (mm): 5.0 x 3.5 CER I2C and SPI frequency pull option LVCMOS or Clipped Sine 1.8 V, 2.5 V, 3.3 V supply voltage
Super-TCXOs SiT5348 1 to 60 MHz SiT5349 60 to 220 MHz SiT5346 1 to 60 MHz SiT5347 60 to 220 MHz	Stability over temperature: ±50 ppb to ±250 ppb g-sensitivity: 0.009 ppb/g total gamma Allan deviation: 1.5 E-11, 1s to 10s No frequency jumps Predictable, part-to-part repeatable performance	Temperature range: -40°C to 105°C Package (mm): 5.0 x 3.2 CER Voltage control or I2C frequency pull option LVCMOS or Clipped Sine 2.5 V, 3.3 V supply voltage
32 kHz TCXO SiT7910 32 kHz	Stability over temperature: ±100 ppb to ±400 ppb Low g-sensitivity	Temperature range: -55°C to 105°C Package (mm): 2.5 x 2.0 CER 1.8 V to 3.3 V supply voltage
Low Jitter Differential Oscillators SiT9551 25 to 644 select frequencies SiT9356 1 to 220 MHz SiT9357 220 to 920 MHz	Stability over temperature: ±20 ppm to ±50 ppm g-sensitivity: 0.04 ppb/g total gamma Phase jitter: 70 fs RMS, 12kHz to 20 MHz PSNR: 9 fs/mV	Temperature range: -55°C to 125°C Package (mm): 2.0 x 1.6, 2.5 x 2.0, 3.2 x 2.5 QFN LVPECL, LVDS, HCSL, Low-power HCSL and FlexSwing™ signaling options Supply voltage: 1.8V, 2.5V, 3.3V
Low g-sensitivity Oscillator SiT8944 1 to 137 MHz SiT8945 1 to 137 MHz	Stability over temperature: ±10 ppm to ±50 ppm g-sensitivity: 0.1 ppb/g Phase jitter: < 0.5 ps RMS	Temperature range: -55°C to 125°C Package (mm): 2.0 x 1.6, 2.5 x 2.0, 3.2 x 2.5, 5.0 x 3.2, 7.0 x 5.0 QFN LVCMOS or LVTTL output Programmable drive strength

Open Architecture Applications

A MOSA chassis has one or more slots to host plug-in cards (PICs) that define the overall function/capability of the system. The chassis backplane provides connectivity of shared services to the appropriate PIC slot in the chassis.

Timing plays a central role in ensuring the coordination, interoperability, and reliability of mission-critical operations. The time reference is provided by the radial clock card, typically referenced to GNSS backed up by holdover oscillator or other methods, and distributed to each of the PICs using IEEE 1588 PTP, NPT, SyncE or other protocols.

Radial clock card

GPS disciplined oscillator (GPSDO)
Assured Positioning, Navigation, and Timing (A-PNT) module or PNT module

Payload card

Software defined radios (SDR)
Communications (COMM)
Electronic warfare (EW)
Signals intelligence (SIGINT)
Up/down converters
Graphics processing units (GPU)
Single board computers
Storage cards

Switch card

Ethernet switches

Example backplane configuration. The radial clock PIC, highlighted in blue, provides the timing signals (i.e. radial clocks) to the other PICs in the chassis.

Endura Advantages

Endura COTS ruggedized oscillators are engineered and warrantied for mission critical applications that operate in harsh environments.

Designed for high shock and vibration environments
Specified, qualified and manufactured using 6-sigma statistical process control and deliver datasheet performance with no derating
100% screened with power cycle over the full temperature range to deliver low DPPM and high reliability
Endura products are programmable parts that are factory-programmed to the customer’s selected configuration to fulfill orders, enabling a wide variety of custom frequencies and configuration options with no NRE and short lead time.