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8761I - Block Diagram
8761I - Pinout


Low Voltage,Low Skew,PCI/PCI-X Clock Generator

The 8761I is a low voltage, low skew PCI / PCI-X clock generator. The 8761I has a selectable REF_CLK or crystal input. The REF_CLK input accepts LVCMOS or LVTTL input levels. The 8761I has a fully integrated PLL along with frequency configurable clock and feedback outputs for multiplying and regenerating clocks with “zero delay”. Using a 20MHz or 25MHz crystal or a 33.333MHz or 66.666MHz reference frequency, the 8761I will generate output frequencies of 33.333MHz, 66.666MHz, 100MHz and 133.333MHz simultaneously. The low impedance LVCMOS/LVTTL outputs of the 8761I are designed to drive 50Ω series or parallel terminated transmission lines.


  • Fully integrated PLL
  • Seventeen LVCMOS/LVTTL outputs, 15Ω typical output impedance
  • Selectable crystal oscillator interface or LVCMOS/LVTTL REF_CLK
  • Maximum output frequency: 166.67MHz
  • Maximum crystal input frequency: 40MHz
  • Maximum REF_CLK input frequency: 83.33MHz
  • Individual banks with selectable output dividers for generating 33.333MHz, 66.66MHz, 100MHz and 133.333MHz simultaneously
  • Separate feedback control for generating PCI / PCI-X frequencies from a 20MHz or 25MHz crystal or 33.333MHz or 66.666MHz reference frequency
  • Cycle-to-cycle jitter: 70ps (maximum)
  • Period jitter, RMS: 17ps (maximum)
  • Output skew: 250ps (maximum)
  • Bank skew: 50ps (maximum)
  • Static phase offset: 0 ± 150ps (maximum)
  • Full 3.3V or 3.3V core, 2.5V multiple output supply modes
  • -40°C to 85°C ambient operating temperature
  • Available in lead-free RoHS-compliant package

Product Specification

Outputs (#)Output TypeOutput Freq Range (MHz)Input Freq (MHz)Inputs (#)Input TypeOutput Banks (#)Core Voltage (V)Output Voltage (V)
17LVTTL, LVCMOS10.000000 - 166.67000010.000000 - 83.3300002LVCMOS, Crystal53.33.3

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
8761CYILFActivePPG64TQFP64IYesTrayCheck Availability
8761CYILFTActivePPG64TQFP64IYesReelCheck Availability


Technical Documentation

Title Other Languages Type Format File Size Datesort icon
Datasheets & Errata
8761i Datasheet Datasheet PDF 216 KB Jan 25, 2016
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-844 Termination - AC Coupling Clock Receivers Application Note PDF 82 KB May 13, 2014
show all (11)
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-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-834 Hot-Swap Recommendations Application Note PDF 67 KB May 6, 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-805 Recommended Ferrite Beads Application Note PDF 38 KB Jan 15, 2014
PCN# : A1602-01(R1) Add Greatek Taiwan as Alternate Assembly Product Change Notice PDF 611 KB Apr 14, 2016
PCN# : A1602-01 Add Greatek Taiwan as Alternate Assembly Product Change Notice PDF 611 KB Feb 15, 2016
PDN# : N-12-22R2 PRODUCT DISCONTINUANCE NOTICE Product Discontinuation Notice PDF 363 KB Jun 14, 2013
show all (4)
PDN# : N-12-22R1 PRODUCT DISCONTINUANCE NOTICE Product Discontinuation Notice PDF 209 KB Feb 28, 2013
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

Software & Tools

Title Type Format File Size Datesort icon
8761I IBIS Model Model - IBIS ZIP 67 KB Nov 4, 2009