25 MHz to 644 MHz Endura Ruggedized Ultra-low Jitter Differential XO


The Endura™ SiT9551 differential oscillator is ideal for FPGA clocking and other high-speed military applications requiring ultra-low jitter, low power, and small size.

This ruggedized oscillator offers 14 common frequencies from 25 MHz to 644.53125 MHz, 70 fs RMS jitter (typ.), and high temperature operation up to 125°C in a QFN package as small as 2.0 x 1.6 mm. The SiT9551 is subjected to SiTime’s Endura process flow to provide high reliability and environmental robustness. The jitter remains unchanged under vibration. The frequency stability is rated at 0.04 ppb/g under typical mechanical vibrations and the oscillator has excellent immunity to power supply noise.

The SiT9551 offers popular output drivers for LVPECL, LVDS, HCSL and low-power HCSL with integrated termination resistors. It also features a unique FlexSwing™ driver that performs like LVPECL but with independent control of VOH and VOL levels to simplify interfacing with chipsets having non-standard input-voltage requirements. The SiT9551 accepts power-supply voltages down to 1.8V for additional power savings.


6-pin Atna
"Specs" "Value"
Oscillator Type XO-DE
Frequency 14 standard frequencies from 25 MHz to 644 MHz
Frequency Stability (ppm) ±20, ±50
Phase Jitter (rms) 70 fs
Output Type LVPECL, LVDS, HCSL, Low-power HCSL, FlexSwing
Operating Temperature Range (°C) -40 to 85, -40 to 105, -40 to 125, -55 to 125
Pin1 Feature No Function, OE active high, OE active low
Voltage Supply (V) 1.8 ±5%, 2.5 ±10%, 3.3 ±10%, 2.25 to 3.63 , 1.71 to 3.63
Package Type (mm²) 2.0 x 1.6, 2.5 x 2.0, 3.2 x 2.5
Features 0.04 ppb/g acceleration sensitivity for harsh environments
Availability Pre-production Sampling

Exceptional dynamic performance in harsh operating conditions

  • 70 fs RMS (typ.) integrated phase jitter, 12 kHz to 20 MHz integration range
  • ±20 ppm frequency stability
  • ±300 ppb 20-year aging, 8x better than quartz, eliminates in-factory calibration required with less stable devices
  • Excellent system performance under environmental stressors

Better acceleration sensitivity and 20x better vibration sensitivity

  • 0.04 ppb/g g-sensitivity, per IAW MIL-PRF-55310 section
  • Minimizes packet loss in high-vibration environments

9 fs/mV power supply induced jitter sensitivity

  • Simplify power supply design

2.0 x 1.6 mm package

  • Industry’s smallest differential package
  • Enables small form-factor systems with stringent jitter requirement

Flexible programmable features

  • 14 common frequencies
  • 1.8 to 3.63 V
  • LVPECL, LVDS, HCSL, Low-power HCSL, FlexSwing: Flexible and low power, output drivers and terminations

Superior reliability

  • 1 billion hours MTBF
  • 6x higher shock survivability
  • Lifetime warranty
  • Reduces field failures due to clock components and associated trouble shooting and repair costs
  • FPGA clocking
  • Airborne communications
  • Command & control
  • Field communications
  • Airframe control
  • Engine management/control
  • Radar
  • Satcom

Frequency Slope (dF/dT) Calculator – Calculate frequency slope over temperature

Jitter Calculator and Plots – Convert phase noise to phase jitter, find phase noise plots