SiTime: SiT5811 Epoch Platform™ OCXO for Network Synchronization and Holdover
The SiT5811 is a MEMS OCXO from SiTime’s Epoch Platform™ family designed for network synchronization, telecom infrastructure, and precision instrumentation with strict holdover and stability requirements. It delivers ±1 ppb over-temperature stability from -40°C to +95°C, a ±0.01 ppb/°C typical frequency slope (ΔF/ΔT), and 4×10⁻¹² HDEV at a 10-second averaging interval in a 9.0 × 7.0 × 3.6 mm package with 420 mW steady-state power consumption.
The device maintains 12-hour holdover under real-world conditions that include an 8°C temperature change, the ITU-T recommended profile, and 1 m/s airflow, with ±0.1 ppb/day aging. TimeFabric™ Holdover Extension expands holdover to 24 hours for extended synchronization continuity. The SiT5811 is the industry’s smallest OCXO to deliver ±1 ppb over-temperature stability, reducing volume by 25× and power by 3× relative to comparable quartz OCXOs while supporting operation from -40°C to +95°C.
Factory programmability supports frequencies from 10 to 60 MHz, supply voltages of 2.5 V, 2.8 V, and 3.3 V, and pull ranges from ±3.125 to ±400 ppm, eliminating quartz-related lead times and per-configuration NRE. I2C and SPI digital frequency tuning with 5×10⁻¹⁴ pull resolution provides precise frequency control. No activity dips or microjumps occur under thermal shock or fast temperature ramps, eliminating the need for screening and burn-in.
Features
- ±1 ppb over-temperature stability from -40°C to +95°C
- ±0.01 ppb/°C typical frequency slope (ΔF/ΔT)
- 4×10⁻¹² HDEV at 10-second averaging interval
- 12-hour holdover under real-world conditions (8°C temperature change, ITU-T profile, 1 m/s airflow)
- ±0.1 ppb/day aging
- TimeFabric™ Holdover Extension to 24 hours
- Industry’s smallest OCXO at 9.0 × 7.0 × 3.6 mm with ±1 ppb over-temperature stability
- 25× lower volume and 3× lower power vs. quartz OCXOs
- 420 mW steady-state power consumption
- Factory-programmable frequency: 10 to 60 MHz; 2.5 V, 2.8 V, and 3.3 V supply options
- Pull ranges from ±3.125 to ±400 ppm
- I2C and SPI digital frequency tuning with 5×10⁻¹⁴ pull resolution
- On-chip power-supply noise filtering; no dedicated LDO required
- No activity dips or microjumps under thermal shock or fast temperature ramps
- 1 billion hours MTBF
- LVCMOS or clipped-sine output
Applications
- 5G infrastructure (RRH, DU)
- ITU-T G.8273.2 Class D
- Small cells
- Data center switches and routers
- Core and edge routers
- Optical transport (OTN, OLT)
- IEEE 1588 boundary clocks and grandmasters
- SONET/SDH Stratum 3E
- Timing servers
- GNSS-disciplined timing modules
- Test and measurement
