156.25 MHz, ±0.1 to ±0.25 ppm Elite RF™ Differential-Ended Precision Super-TCXO
LoginThe SiT5977 is a differential ended ±100 ppb precision MEMS Super-TCXO® designed for high stability and low jitter applications, such as Smart NICs, acceleration cards, switches, and compute node applications.
Combining SiTime’s DualMEMS® technology with a low-noise digital PLL, this chip delivers excellent jitter, dynamic stability in the presence of airflow and thermal excursions, and resistance to shock and vibration. Multiple on-chip regulators filter power supply noise, eliminating the need for an external LDOs.
The SiT5977 offers frequency control (DCTCXO) via an I2C/SPI interface with 0.05 ppt resolution and up to ±400 ppm pull range. This unique functionality, along with 80 fs phase jitter, can eliminate the need for a jitter cleaner and enable new architectural options.
Related Blog: Product Spotlight: SiT5977 Super-TCXO Enables New Architecture for Greater AI Workload Efficiency in Datacenters

"Specs" | "Value" |
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Frequency | 156.25 MHz |
Frequency Stability (ppm) | ±0.1, ±0.2, ±0.25 |
Operating Temperature Range (°C) | -40 to +85 |
Package Type (mm²) | 5.0 x 3.5, 10-pin |
Phase Jitter (rms) | 80 fs |
Pull Range (ppm) | ±3.125, ±6.25, ±10, ±12.5, ±25, ±50, ±100, ±200, ±400 |
Voltage Supply (V) | 3.3 |
Features | Best-in-class dynamic stability with ±1 ppb/°C frequency over temperature slope (dF/dT) |
Availability | Pre-Production Sampling |
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5032 10-Pin Ceramic MEMS Oscillator (Top & Bottom Angled View)
- Environmentally robust with ±1 ppb/°C frequency slope (dF/dT) for optimum performance under airflow, thermal shock
- Capable of driving 800G and higher links via 80 fs phase jitter and LVDS differential output
- Enables embedded control loops with precise digital tuning of output frequency (DCTCXO)
- Digital control via I2c/SPI
- Up to ±400 ppm pull range
- Frequency pull resolution down to 0.05 ppt (5e-14)
- Eliminates link flaps from activity dips or micro jumps associated with quartz devices
- Resistant to shock, vibration and board bending
- Eliminates external LDOs via on-chip voltage regulators
- ±100 ppb frequency stability over temperature with DualMEMS architecture
- 156.25 MHz output frequency enabling high-speed SerDes and 800G links
- Small 5.0 x 3.5 mm package (footprint compatible with 5.0 x 3.2 mm package)
- Contact SiTime for -40°C to 105°C operating temperature and other output options

To support system level synchronization, this chip integrates digital control (DCTCXO) via a I2C/SPI interface to adjust the output frequency with a fine resolution. Additionally, multiple on-chip regulators filter power supply noise, eliminating the need for an external LDO (low-dropout) regulator.
- Network Interface and Accelerator Cards
- Switches
- IEEE 1588 Boundary Clocks & Grandmasters
- SerDes
- 4G / 5G RRH, DU
- Small Cells
- RF Signal Chain
- Radar
- Satellite Base Station
- Microwave Backhaul
- Instrumentation
- Test & Measurement
- 5G Radios
Frequency Slope (dF/dT) Calculator – Calculate frequency slope over temperature
Time Error Simulation Software – Simulate and analyze the impact of the local oscillator
TimeMaster Configuration Software – Configure and evaluate oscillators via I2C/SP
Reliability Calculator – Get FIT/MTBF data for various operating conditions
SiTime Studio – A Phase-noise productivity tool
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