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FemtoClock® NG Jitter Attenuator and Clock Synthesizer

The 8V44N4614 is a FemtoClock® NG Clock Generator. The device has been designed for frequency generation in high-performance systems such wireless base-band boards, for instance to drive the reference clock inputs of processors, PHY, switch and SerDes devices. The device is very flexible in frequency programming. It allows to generate the clock frequencies of 156.25MHz, 125MHz, 100MHz and 25MHz individually at three output banks. One output bank supports configurable LVDS, LVPECL, the other two output banks support LVCMOS output levels. All outputs are synchronized on the incident rising edge, regardless of the selected output frequency. Selective single-ended LVCMOS outputs can be configured to invert the output phase, effectively forming differential LVCMOS output pairs for noise reduction. The PLL reference signal is either a 25MHz, 50MHz, 100MHz or 200MHz differential or single-ended clock.
The device is optimized to deliver excellent period and cycle-to-cycle jitter performance, combined with good phase noise performance, and high power supply noise rejection.

The device is configured through an SPI serial interface. Outputs can be configured to any of the available output frequencies. Two hardware pins are available for selecting pre-set output enable/disable configurations. In each of these pre-set configurations, each output can be enabled/disabled individually. A separate test mode is available for an increase or decrease of the output frequencies in 19.53125ppm steps independent on the input frequency. The device is packaged in a lead-free (RoHS 6) 48-lead VFQFN package. The extended temperature range supports wireless infrastructure, telecommunication and networking end equipment requirements.


  • Clock generator for wireless base-band systems
  • Drives reference clock inputs of processors, PHY, switch and
    SerDes devices
  • FemtoClock® NG technology
  • Three low-skew, differential LVDS, LVPECL configurable clock
  • Ten low-skew, LVCMOS/LVTTL clock outputs
  • Input: 200MHz, 100MHz, 50MHz, 25MHz single-ended  
    (LVCMOS) or differential reference clock (LVDSLVPECL)
  • Output clocks support 156.25MHz, 125MHz, 100MHz and 25MHz
  • Individual output disable (high-impedance)
  • Two sets of output enable configurations
  • PLL lock detect output
  • Test mode with frequency margining with 19.53125ppm steps
    (range ±507.8125ppm)
  • LVCMOS (1.8V, JESD8-7A) compatible SPI programming
  • Cycle-to-cycle jitter: 10ps (typical)
  • RMS period jitter: 1.6ps (typical)
  • Phase noise (12kHz - 20MHz): 0.40ps (typical)
  • 3.3V core and output supply
  • -40°C to +85°C ambient operating temperature
  • Lead-free (RoHS 6) 48-lead VFQFN packaging

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
8V44N4614NLGIActiveNLG48P1VFQFPN48IYesTrayCheck Availability
8V44N4614NLGI/WActiveNLG48P1VFQFPN48IYesReelCheck Availability
8V44N4614NLGI8ActiveNLG48P1VFQFPN48IYesReelCheck Availability


Technical Documentation

Title Type Format File Size Datesort icon
Datasheets & Errata
8V44N4614 Datasheet Datasheet PDF 734 KB Mar 23, 2015
Apps Notes & White Papers
AN-828 Termination - LVPECL Application Note PDF 229 KB Jul 5, 2016
AN-831 The Crystal Load curve Application Note PDF 308 KB Sep 22, 2014
AN-844 Termination - AC Coupling Clock Receivers Application Note PDF 82 KB May 13, 2014
show all (21)
AN-846 Termination - LVDS Application Note PDF 50 KB May 13, 2014
AN-842 Thermal Considerations in Package Design and Selection Application Note PDF 403 KB May 12, 2014
AN-840 Jitter Specifications for Timing Signals Application Note PDF 349 KB May 8, 2014
AN-803 Crystal Timing Budget and Accuracy for IDT Timing Clock Products Application Note PDF 44 KB May 8, 2014
AN-839 RMS Phase Jitter Application Note PDF 149 KB May 7, 2014
AN-838 Peak-to-Peak Jitter Calculations Application Note PDF 32 KB May 7, 2014
AN-836 Differential Input to Accept Single-ended Levels Application Note PDF 37 KB May 6, 2014
AN-835 Differential Input with VCMR being VIH Referenced Application Note PDF 77 KB May 6, 2014
AN-837 Overdriving the Crystal Interface Application Note PDF 50 KB May 6, 2014
AN-834 Hot-Swap Recommendations Application Note PDF 67 KB May 6, 2014
AN-832 Timing Budget and Accuracy Application Note PDF 48 KB May 6, 2014
AN-830 Quartz Crystal Drive Level Application Note PDF 59 KB May 5, 2014
AN-827 Application Relevance of Clock Jitter Application Note PDF 1.06 MB Apr 24, 2014
AN-815 Understanding Jitter Units Application Note PDF 476 KB Apr 24, 2014
AN-802 Crystal-Measuring Oscillator Negative Resistance Application Note PDF 52 KB Mar 12, 2014
AN-801 Crystal-High Drive Level Application Note PDF 109 KB Jan 15, 2014
AN-805 Recommended Ferrite Beads Application Note PDF 38 KB Jan 15, 2014
AN-806 Power Supply Noise Rejection Application Note PDF 353 KB Jan 15, 2014