Si5342H and Si5344H Coherent Optical Clocks

The Si5344H/Si5342H coherent optical clock is purpose-built to address the needs of coherent optical communications applications. Silicon Labs’ coherent clock utilizes specialized high-speed dividers and drivers to deliver up to 2.7 GHz clocks with ultra-low 50 fs-rms phase jitter required  coherent transceiver DACs and ADCs. The Si5344H/Si5342H leverages 4th generation DSPLL technology to clean recovered clocks, DCO mode for coherent DSP control via a fast SPI interface, and integrated MultiSynth fractional synthesis to support eye-diagram monitors, FEC, and MUX/DEMUX clock requirements. Such single-chip integration enables designers to meet the stringent performance, form-factor, and power requirements demanded in 100G/200G/400G line cards and modules.


  • Up to 2.7 GHz outputs replace VCSOs and synthesizers
  • Ultra-low phase jitter: 50 fs-rms (100kHz - 20 MHz)
  • Digitally selectable loop bandwidth for cleaning recovered clocks
  • Digitally controlled oscillator (DCO) with fast SPI interface
  • MultiSynth fractional synthesis for any-frequency clock support
  • Single-chip solution in a small 7 x 7 mm, QFN44 package
  • Si5344H: 4-outputs, Si5342H: 2-outputs

Evaluate Coherent Optical Clocks

The easiest way to begin development with the Coherent Optical Clocks family is with the Si5344H-EVB kit. The development kit make it easy to move from ClockBuilder Pro device configuration to hands-on performance evaluation.

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Product Matrix

Part Number Data Sheet Dev KIt Description Control Reference Inputs Clock Outputs Input Frequency (MHz) Output Frequency (MHz) Output Format(s) Phase Jitter (RMS) (ps) VDD (V) VDDO (V) Package Type Package Size (mm) Output Bin Clock Generators Jitter Attenuating Clocks Synchronous Ethernet/1588 PCI Express Clocks 4G/LTE Wireless Clocks Intel x86 Clocks
Si5344H-EVB 100G/400G Coherent Optics Clock, 4-Output, <2.7GHz, Jitter Attenuator, DCO I2C/SPI 2 4 8 750 100 2750 CML, HCSL, LVCMOS, LVDS, LVPECL 0.1 1.8; 2.5; 3.3 1.8; 2.5; 3.3 QFN44 7x7 <= 4 No Yes No No No No
Si5344H-EVB 100G/400G Coherent Optics Clock, 2-Output, <2.7GHz, Jitter Attenuator, DCO I2C/SPI 4 2 8 750 100 2750 CML, HCSL, LVCMOS, LVDS, LVPECL 0.1 1.8; 2.5; 3.3 1.8; 2.5; 3.3 QFN44 7x7 <= 4 No Yes No No No No
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