SiTime ENDR-TTT: A MEMS Super-TCXO for GNSS Holdover and Anti-Spoofing

 ENDR-TTT Super-TCXO (Temperature-Compensated Crystal Oscillator)

SiTime has recently introduced the ENDR-TTT, Endura Super-TCXO (Temperature-Compensated Crystal Oscillator), a rugged, ultra-stable MEMS temperature-compensated oscillator designed for GNSS-based position, navigation, and timing (PNT) systems that remain accurate during signal loss, jamming, or spoofing.

Designed for aerospace, defense, and industrial GNSS receivers, the oscillator provides extended holdover performance when GNSS signals are unavailable or degraded. It delivers up to 20× longer holdover and 20× better PNT accuracy compared to conventional solutions, with ±50 ppb frequency stability over temperature, extremely low g-sensitivity (0.004 ppb/g), and resistance to shock up to 30,000 g. The device operates across a wide −55°C to +125°C range, supports optional I²C or SPI digital frequency pulling for fine tuning, and offers ±0.5 ppm aging over 20 years, eliminating the need for field recalibration in long-life systems.

 ENDR-TTT Super-TCXO (Zoomed)

SiTime ENDR-TTT Specifications:

• Oscillator type: Ruggedized MEMS Super-TCXO (TCXO / DCTCXO variants)
• Technology: DualMEMS temperature sensing, TurboCompensation
• Frequency:
  • Range: Factory-programmed from 1 MHz to 105 MHz
  • Stability: ±50 ppb to ±500 ppb (multiple stability grades)
• Sensitivity: 0.004 ppb/g (typical)
• Output types: Unregulated or regulated LVCMOS, clipped-sine
• Phase noise: Low phase noise (–151 dBc/Hz @ 10 kHz offset) suitable for precision GNSS receivers
• Acceleration sensitivity: 0.004 ppb/g (typical)
• Digital frequency pulling:
  • ±200 ppm range
  • 3.64 ppt resolution
  • 16 factory-programmed pull-range options
• Interface: I²C or SPI
• Misc: Integrated voltage regulators (no external LDO required)
• Power:
  • Supply voltage: 1.8 V to 3.3 V (Supports 1.8 V, 2.5 V, and 3.3 V logic levels)
  • Consumption: 21 mW @ 1.8 V
• Operating temperature: –55°C to +125°C
• Package: 5.0 × 3.2 mm, 10-pin ceramic surface-mount
• Aging: ±0.5 ppm over 20 years (no field recalibration required)
• Shock resistance:
  • 30,000 g operational shock
  • Up to 120,000 g contact shock
• Compliance: RoHS and REACH compliant; lead-free, halogen-free

SiTime provides TimeMaster Configuration Software, which communicates with the oscillator over I²C or SPI. The tool allows engineers to configure factory-programmed pull ranges, apply high-resolution digital frequency pulling (up to ±200 ppm with ppt-level resolution), read back internal temperature data, and evaluate timing behavior relevant to GNSS holdover and synchronization. It is primarily intended for device configuration, characterization, and system-level timing validation rather than runtime control.

ENDR-TTT Applications

At the time of writing, the ENDR-TTT MEMS GNSS TCXO is currently sampling, with mass production scheduled for Q1 2026, and is available through SiTime’s direct sales channels and authorized distributors. More information can be found on companies products page and press release page.

Images used courtesy of SiTime