Epoch Platform Size Comparison

Endura Epoch Platform – Trustworthy OCXOs

Positioning navigation and timing (PNT) systems depend on precision timing. The primary source of timing for most PNT system is GPS or other GNSS. GPS may be intentionally or unintentionally disrupted due to jamming, spoofing, inclement weather, tree canopy or inside buildings. When the GPS signal is disrupted, critical equipment can’t perform unless there is an ultra-stable local clock. Without a trustworthy clock, disruptions can have catastrophic consequences in military or aerospace operations.  

The Endura Epoch Platform™ of ruggedized MEMS OCXOs (oven-controlled oscillators) solve the long-standing problems of legacy quartz OCXOs, which are inherently less reliable, prone to performance degradation under shock and vibrations, and are bulky and power hungry.  Endura OCXOs provide benchmark performance in frequency stability, size, and power consumption compared to standard +1ppb OCXOs.

Device* Datasheet Stability Holdover

(3 µs)

Frequency Temp. Range Size (mm) Features
SiT7111 ±1 ppb 24 hours 10 to 60 MHz Up to
-40 to +95°C
9.0 x 7.0 x 3.6 420 mW power consumption,
±10 ppt/°C frequency slope
SiT7112 ±1 ppb 24 hours 60 to 220 MHz Up to
-40 to +95°C
9.0 x 7.0 x 3.6 460 mW power consumption,
±10 ppt/°C frequency slope
SiT7101 ±3, 5 ppb 12 hours 10 to 60 MHz Up to
-40 to +95°C
9.0 x 7.0 x 3.6 420 mW power consumption,
±20 ppt/°C frequency slope
SiT7102 ±3, 5 ppb 12 hours 60 to 220 MHz Up to
-40 to +95°C
9.0 x 7.0 x 3.6 460 mW power consumption,
±20 ppt/°C frequency slope

* All devices offer: (1) digital frequency pulling (DCOCXO) via I2C/SPI with up to ±800 ppm pull range and 0.05 ppt (5e-14) resolution; (2) supply voltage options of 2.5V, 2.8V, and 3.3V; and (3) regulated LVCMOS or clipped sinewave output.

Request a Sample

Silicon reliability

Endura Epoch OCXOs are manufactured in industry standard microelectronics factories that use high-purity materials and environments managed under statistical process control. Endura OCXOs undergo statistical qualification which qualify the design and process for high volume production. This results in reliability that is 30X higher than quartz OXCOs.


A ruggedized OCXO for harsh environments

Endura Epoch OCXO are designed and tested to perform in high shock and vibration environments. They demonstrate 0.01 ppb/g g-sensitivity under 10G vibration without external vibration compensation, which is 20X better than commercially available, vibration-rated OCXOs. This eliminates the need for bulky and heavy vibration-compensated OCXOs or for designing a custom vibration dampening system.

Endura Epoch OCXOs outperform commercial vibration-rated OCXOs in the following areas.

  • 0.01 ppb/g g-sensitivity – 70x better
  • ±1 ppb stability over temperature – 20x better
  • ±0.01 ppb/°C ΔF/ΔT, stability over temperature slope – 10x better
  • 5E-12 Allan deviation (ADEV) – 4x better
  • 0.1 ppb/day short term aging – 10x better


A low SWaP solution

Endura Epoch OCXOs deliver significant improvements in size, weight, and power (SwaP) while delivering benchmark performance. They offer unmatched ease-of-use, eliminate the restrictions on board placement due to thermals, EMI, footprint or height, and they reduce the need for vibration dampening.

Performance Multiplier of Endura Epoch vs. Low-g quartz OCXO


Endura Epoch OCXOs solve the size and power issues of traditional vibration rated OCXOs. Designed as surface-mount devices, they can go through reflow at the same time as the other components on the board.

  • 9.0 x 7.0 x 3.6 mm – up to 20X smaller
  • 0.35 grams – up to 300X less weight than vibration compensated designs
  • 420 mW typical (3.3V) power consumption – up to 2X lower power


Delivering an ultra-stable, ultra-resilient local clock

SiTime's Endura Epoch Platform is a game-changer in precision timing. During GPS disruption or “holdover”, PNT system performance is driven by the time error of the local clock. Endura OCXOs provide benchmark stability during holdover with a time error of only 3 µs over 24 hours without aging compensation.

Endura Epoch OCXO holdover performance is achieved due to excellent Allan deviation and low daily aging of 0.1 ppb/day.

Endura Epoch OCXO Is the Stable PNT OCXO during GPS disruption

Time error of Endura Epoch OCXO up to 24 hours without aging compensation at constant temperature.


Endura Epoch OCXO outperforms quartz OCXO

Hadamard Deviation (HDEV) under Airflow

SiT7111 is 3x-10x More Resistant to Airflow, Enabling Better Holdover

Comparison of measured Hadamard deviation (Allan deviation without daily aging) beyond 10,000 s between Endura Epoch OCXO and a non-vibration rated, ±1ppb commercial OCXO. In addition to having 3 times lower HDEV, Endura Epoch OCXO also shows part to part repeatability which results from silicon manufacturing.

Frequency Stability Over Temperature

Endura Epoch OCXO is rated at ±1 ppb frequency stability vs. temperature over -40 to 95°C with a dF/dT of ±0.1 ppb/°C to provide superior holdover even during temperature swings, being diurnal, external or internal to the system.

SiTime’s Tight Silicon Production Process Enables Dependable FvT

Comparison of frequency stability over -40 to 85°C of ±1 ppb Endura Epoch OCXO with a best-in-class non-vibration rated, ±1 ppb commercial OCXO.

Frequency Over Temperature Slope (dF/dT)

SiT7111 is 2x-10x Better on ΔF/ΔT, Enabling Longer Holdover

Comparison of frequency stability vs. temperature of ±1 ppb Endura Epoch OCXO with a best-in-class non-vibration rated, ±1ppb commercial OCXO.


The Endura Epoch Platform™ of ruggedized silicon MEMS OCXOs provide unmatched performance in reliability, SWaP, frequency stability over temperature, temperature changes, vibration and time during holdover compared to commercial solutions available today. This noticeable raises the bar in system performance to level not achievable today.

Ready to transform your design? Let's get started!