ORAN Distributed Unit
5G Open RAN brings greater flexibility to networks that are becoming increasingly dense with equipment deployed further from the core, sometimes in less-controlled environments. At the same time, these components need precise synchronization to avoid data packet loss and network interruptions.
This puts a greater demand on the distributed unit (DU) timing solution as it synchronizes the time reference from the core to the fronthaul switch and out to the RU. If the timing reference is lost, the DU must maintain an accurate output clock (holdover) until the connection to the reference is restored. SiTime provides a complete all-silicon MEMS clock tree that is more robust and easy to configure for accurate IEEE 1588 timing.
SiTime MEMS Timing Benefits
Complete MEMS clock treePrecision MEMS OCXO 4 input network synchronizer Integrated MEMS eliminate quartz reliability issues |
More robust in real world conditions±40 ppt/°C dF/dT for accurate IEEE 1588 I2C monitoring for simplified compensation Immunity to board level noise |
Easily configurable clockingHitless switching for minimal disruptions Flexibility of 4 independent time domains Low wander mode for optimal holdover |
Clock Tree for Open RAN with IEEE 1588
Clock Tree for NPU Based Open RAN DU
MEMS Timing Solutions for Precision Synchronization
| Devices | Function | Frequency | Key Features |
|---|---|---|---|
| SiT5711 OCXO |
Stability Engine for IEEE 1588 Clock Recovery |
1 to 60 MHz | ±5 ppb, ±40 ppt/°C dF/dT |
| SiT5721 Digitally Controlled OCXO | 1 to 60 MHz | ±40 ppt/°C dF/dT, I2C Programmable | |
| SiT95147 Network Synchronizer |
Monitor SyncE and eCPRI inputs, facilitate IEEE 1588 loop |
8 kHz to 2.1GHz | 120 fs jitter for SyncE, 4 inputs and 8 outputs |
| SiT95148 Network Synchronizer | 8 kHz to 2.1GHz | 120 fs jitter for SyncE, 4 inputs and 11 outputs |
MEMS Timing Outperforms Quartz
Better Stability |
Better Frequency Slope |
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Better Allan Deviation |
Faster Warm Up |
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Lower Supply Voltage Sensitivity |
Fastest Hitless Switching |
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Watch Video: SiTime MEMS Timing Solutions for Open RAN
Application Notes and Papers
• Adaptive Drift Compensation for Holdover Oscillators
• AN10063 TCXO and OCXO Stability and System Impact Beyond Rated Temperature
• AN10064 Improved System Performance with Digital Frequency Tuning in Precision Super-TCXOs
• AN20003 SiT9514x Power Supply Noise Rejection
• AN20011 SiT9514x Dynamic Control of Outputs
• AN10052 IEEE 1588 Precision Time Protocol (PTP) in ITU-T Standards
See full list of related applications notes
Videos
• SiTime Elite Super-TCXO Dynamic Performance vs. Quartz TCXO
