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.

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SiTime MEMS Timing Benefits

Complete MEMS clock tree

Precision 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 clocking

Hitless switching for minimal disruptions

Flexibility of 4 independent time domains

Low wander mode for optimal holdover

Clock Tree for Open RAN with IEEE 1588

DU block diagramsitimeSiT57xxsitime.comsitime.comSiT53xxSiT95145SiT9514xsitime.com

Clock Tree for NPU Based Open RAN DU

Microwave block diagramSiT9514xsitime.comsitime.comsitime.comSiT57xxSiT53xxSiT5721SiT95145sitime.comsitime.com

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





Better Allan Deviation

Faster Warm Up





Lower Supply Voltage Sensitivity

Fastest Hitless Switching

graphs_o-ran_Lower_Supply_Voltage_Sensitivity graphs_o-ran_Fastest_Hitless_Switching

Watch Video: SiTime MEMS Timing Solutions for Open RAN

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