Skip to main content


Crystal or Differential to Differential Clock Fanout Buffer

The 8T39S10I is a high-performance clock fanout buffer. The input clock can be selected from two differential inputs or one crystal input. The internal oscillator circuit is automatically disabled if the crystal input is not selected. The crystal pin can be driven by single-ended clock when crystal is bypassed.The selected signal is distributed to ten differential outputs which can be configured as LVPECL, LVDS or HSCL outputs. In addition, an LVCMOS output is provided. All outputs can be disabled into a high-impedance state. The device is designed for signal fanout of high-frequency, low phase-noise clock and data signal. The outputs are at a defined level when inputs are open circuit or tied to ground. It is designed to operate from a 3.3V or 2.5V core power supply, and either a 3.3V or 2.5V output operating supply.


  • Two differential reference clock input pairs
  • Differential input pairs can accept the following differential input levels: LVPECL, LVDS, HCSL
  • Crystal Oscillator Interface
  • Crystal input frequency range: 10MHz to 40MHz
  • Maximum Output Frequency
    • LVPECL - 2GHz
    • LVDS - 2GHz
    • HCSL - 250MHz
    • LVCMOS - 250MHz
  • Two banks, each has five differential output pairs that can be configured as LVPECL or LVDS or HCSL
  • One single-ended reference output with synchronous enable to avoid clock glitch
  • Output skew: (Bank A and Bank B at the same output level: 70ps (max)
  • Part-to-part skew: 250ps (max)
  • Additive RMS phase jitter: 0.153ps (typical)
  • Supply voltage modes:
    • VDD/VDDO
    • 3.3V/3.3V
    • 3.3V/2.5V
    • 2.5V/2.5V
  • -40°C to 85°C ambient operating temperature
  • Lead-free (RoHS 6) packaging

Product Specification

Outputs (#)Output TypeOutput Freq Range (MHz)Input Freq (MHz)Inputs (#)Input TypeOutput Banks (#)Core Voltage (V)Output Skew (ps)Additive Phase Jitter Typ RMS (fs)
11LVCMOS, LVDS, LVPECL, HCSL0.000000 - 2000.0000000.000000 - 2000.0000003HCSL, LVDS, LVPECL, Crystal22.5, 3.332153

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
8T39S10NLGIActiveNLG48P1VFQFPN48IYesTrayCheck Availability
8T39S10NLGI8ActiveNLG48P1VFQFPN48IYesReelCheck Availability


Technical Documentation

Title Other Languages Type Format File Size Datesort icon
Datasheets & Errata
8T39S10I Data Sheet Datasheet PDF 887 KB Mar 20, 2014
Apps Notes & White Papers
AN-828 Termination - LVPECL Application Note PDF 229 KB Jul 5, 2016
AN-845 Termination - LVCMOS Application Note PDF 62 KB May 13, 2014
AN-846 Termination - LVDS Application Note PDF 50 KB May 13, 2014
show all (13)
AN-844 Termination - AC Coupling Clock Receivers Application Note PDF 82 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-833 Differential Input Self Oscillation Prevention Application Note PDF 94 KB May 6, 2014
AN-835 Differential Input with VCMR being VIH Referenced Application Note PDF 77 KB May 6, 2014
AN-836 Differential Input to Accept Single-ended Levels Application Note PDF 37 KB May 6, 2014
AN-834 Hot-Swap Recommendations Application Note PDF 67 KB May 6, 2014
AN-815 Understanding Jitter Units Application Note PDF 476 KB Apr 24, 2014
AN-827 Application Relevance of Clock Jitter Application Note PDF 1.06 MB Apr 24, 2014
AN-805 Recommended Ferrite Beads Application Note PDF 38 KB Jan 15, 2014
IDT Clock Generation Overview 日本語 Overview PDF 1.83 MB Apr 28, 2016
IDT Clock Distribution Overview 日本語 Overview PDF 3.79 MB Apr 25, 2016