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83PN15639I - Block Diagram
83PN15639I - Pinout


Programmable FemtoClock® NG 3.3V,2.5V LVPECL Oscillator Replacement

The IDT83PN15639I is a programmable LVPECL synthesizer that is "forward" footprint compatible with standard 5mm x 7mm oscillators. The device uses IDT's fourth generation FemtoClock® NG technology for an optimum of high clock frequency and low phase noise performance. Forward footprint compatibility means that a board designed to accommodate the crystal oscillator interface and the optional control pins are also fully compatible with a canned oscillator footprint - the canned oscillator will drop onto the 10-VFQFN footprint for second sourcing purposes. This capability provides designers with programability and lead time advantages of silicon/crystal based solutions while maintaining compatibility with industry standard 5mm x 7mm oscillator footprints for ease of supply chain management. Oscillator-level performance is maintained with IDT's 4th Generation FemtoClock® NG PLL technology, which delivers sub 0.2ps rms phase jitter. The IDT83PN15639I defaults to 156.25MHz using a 25MHz crystal but can also be set to one of four different frequency multiplier settings to support a wide variety of applications. The table below shows some of the more common application settings.


  • Fourth Generation FemtoClock® NG technology
  • Footprint compatible with 5mm x 7mm differential oscillators
  • One differential LVPECL output pair
  • Crystal oscillator interface which can also be overdriven using a single-ended reference clock
  • Output frequency: 156.25MHz
  • Crystal/input frequency: 25MHz, 12pF parallel resonant crystal
  • VCO range: 2GHz – 2.5GHz
  • RMS phase jitter @ 156.25MHz, 10kHz – 1MHz: 0.187ps (typical)
  • Full 3.3V or 2.5V operating supply
  • -40°C to 85°C ambient operating temperature
  • Available in lead-free (RoHS 6) package

Product Specification

Input TypeInputs (#)Output TypeOutputs (#)

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
83PN15639ANRGIActiveNRG10VFQFPN10IYesTrayCheck Availability
83PN15639ANRGI8ActiveNRG10VFQFPN10IYesReelCheck Availability


Technical Documentation

Title Type Format File Size Datesort icon
Datasheets & Errata
83PN15639 Datasheet Datasheet PDF 333 KB Aug 17, 2016
User Guides & Manuals
Timing Solutions for Cavium Processor Designs Guide PDF 810 KB Mar 9, 2016
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 (20)
AN-842 Thermal Considerations in Package Design and Selection Application Note PDF 403 KB May 12, 2014
AN-803 Crystal Timing Budget and Accuracy for IDT Timing Clock Products Application Note PDF 44 KB May 8, 2014
AN-840 Jitter Specifications for Timing Signals Application Note PDF 349 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-832 Timing Budget and Accuracy Application Note PDF 48 KB May 6, 2014
AN-834 Hot-Swap Recommendations Application Note PDF 67 KB May 6, 2014
AN-836 Differential Input to Accept Single-ended Levels Application Note PDF 37 KB May 6, 2014
AN-837 Overdriving the Crystal Interface Application Note PDF 50 KB May 6, 2014
AN-835 Differential Input with VCMR being VIH Referenced Application Note PDF 77 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-806 Power Supply Noise Rejection Application Note PDF 353 KB Jan 15, 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
PCN# : W1308-01 Change of Passivation Thickness Product Change Notice PDF 941 KB Sep 11, 2013