VTOL and Commercial UAVs

An unmanned passenger drone (air taxi) flying in the sky

VTOL aircraft and UAVs are exposed to harsh conditions such as vibration and shock. They need a ruggedized timing solution that is as tough as the environment in which they operate. SiTime Endura™ ruggedized MEMS oscillators provide robust performance with the best acceleration sensitivity, better phase noise under vibration, and excellent stability over temperature.

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SiTime Endura Ruggedized Timing Benefits

Robust in Harsh Conditions

Up to -55°C to 105°C

0.009 ppb/g g-sensitivity

70g vibration survivability

30,000g shock survivability

Jitter unchanged under vibration

1 ppb/°C dF/dT temp slope

Easy to use, simplifies design

Smaller package

Integrated LDOs and DCXO option

Fewer external components needed

No derating necessary

0.2 ps/mW PSNR

No OCXO headaches with Super-TCXOs

Higher Reliability

2B hours MTBF, <0.5 DPPM

No frequency jumps or activity dips

No cold start issues

6-sigma process control

COTS screened over temp

±400 ppb 20-year aging

VTOL Aircraft and UAVs Need Robust and Reliable Timing

Uncrewed aerial vehicles (UAV)/drone technology has been used by the military for some time. Advancements and miniaturization in the electronics, batteries, motors and sensors of UAVs have extended the benefits of the technology to many commercial applications such as agriculture, surveying, aerial photography, remote inspection, search and rescue, and air taxis. Timing solutions that operate reliably in the dynamic environments of UAVs are no longer elusive.

UAVs must operate, navigate and communicate through take off, cruise, and landing, even in air turbulence and adverse conditions. They use novel and complex technologies such as electrical vertical take-off and landing (VTOL). Many functionalities, previously delivered in separate subsystems, are now integrated and are packed into a small space to make UAVs agile.

Delivering stable operation, precise navigation and deterministic communication, while managing power supply noise and board layout, presents a challenge in designing the timing solution. SiTime Endura™ commercial off-the-shelf (COTS) ruggedized MEMS oscillators meet these challenges. Ruggedized Endura timing solutions are extremely reliable and remain stable and with low jitter over a wide temperature range and under severe vibrations.

VTOL and Commercial UAVs Block Diagram

SiTime Endura Advantages

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

Designed for wide temperature operation from -55°C to 125°C and 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
Customers find that Endura MEMS oscillators operate better than military and Hi-Rel oscillators at commercial price point

Endura MEMS Timing for VTOL and Commercial UAVs

Devices	Key Features	Key Values
Single ended oscillators SiT8944 1 to 60 MHz SiT8945 60 to 220 MHz	±10 ppm to ±50 ppm frequency stability over temp range -55°C to 105°C 0.1 ppb/g frequency stability Low jitter: < 0.5 ps RMS ^[1] 1.8 V, 2.5 V, 3.3 V	Better frequency and jitter margin enhance system stability and robustness Easy availability of any device configuration Minimizes EMI from the oscillator
Differential oscillators SiT9346 1 to 220 MHz SiT9347 220 to 725 MHz	Low jitter: 0.23 ps RMS ^[1] LVPECL, LVDS, HCSL 2.5 to 3.3 V -40°C to 105°C 3.2 x 2.5 mm package	Meets demanding jitter requirements Small PCB footprint, easier layout Easy design due to flexibility MEMS reliability
DCXOs SiT3541 1 to 220 MHz SiT3542 220 to 625 MHz	Digital frequency control: I²C/SPI ±3200 ppm pull range 5 ppt resolution ±10 ppm to ±50 ppm frequency stability over temp range	Eliminates need for external DAC to control a VCXO Better accuracy, lower noise due to digital control
Super-TCXOs SiT5146 1 to 60 MHz SiT5147 1 to 60 MHz	±0.5 to ±2.5 ppm stability ±15 ppb/°C frequency slope 0.009 ppb/g acceleration sensitivity -55°C to 105°C	Extremely stable under shock and vibrations No change in phase noise under vibrations Minimizes link drops due to shock, vibration, or temperature change I²C/SPI digital control to speed design
Super-TCXOs SiT5346 1 to 60 MHz SiT5347 60 to 220 MHz	±0.1 to ±0.25 ppm stability ±1 ppb/°C 0.009 ppb/g acceleration sensitivity -40°C to 105°C	Extremely stable under shock and vibrations No change in phase noise under vibrations Minimizes link drops due to shock, vibration, or temperature change I²C/SPI digital control to speed design
Super-TCXOs SiT5348 1 to 60 MHz SiT5349 60 to 220 MHz	±50 ppb stability ±1 ppb/°C 0.009 ppb/g acceleration sensitivity -40°C to 105°C	Extremely stable under shock and vibrations No change in phase noise under vibrations Minimizes link drops due to shock, vibration, or temperature change I²C/SPI digital control to speed design

^[1] 12 kHz to 20 MHz integration range.

Endura Timing Outperforms Quartz

SiTime devices are typically smaller than crystal devices and can be available in plastic packages. Due to the coefficient of thermal expansion (CTE) being closer to the CTE of a PCB, plastic packages improve the solder joint reliability compared to the ceramic packages required for crystal resonators and oscillators.

SiTime differential oscillators offer state-of-the-art jitter performance.

SiTime Endura products eliminate the headaches of quartz oscillators. They simplify design, reduce problems discovered during verification and qualification, shorten product development and time to certification, support production ramp up and continuous supply, and ease trouble shooting through the life of the product.

Endura SiT5348 Super-TCXO Frequency Stability	Endura SiT5348 Super-TCXO Phase Noise Under Vibration
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Endura Best-in-Class-Aging	Endura Lower Acceleration (g) Sensitivity
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Endura Timing Outperforms Quartz

▀ SiTime ▀ Quartz

Acceleration Sensitivity

Mechanical Shock

Quality

Reliability MTBF (Million Hours)

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VTOL and Commercial UAVs