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8705I - Block Diagram
8705I - Pinout


Zero Delay, Differential-to-LVCMOS/LVTTL Clock Generator

The 8705I is a highly versatile 1:8 Differential-to- LVCMOS/LVTTL Clock Generator. The 8705I has two selectable clock inputs. The CLK1, nCLK1 pair can accept most standard differential input levels. The single ended CLK0 input accepts LVCMOS or LVTTL input levels.The 8705I has a fully integrated PLL and can be configured as zero delay buffer, multiplier or divider and has an input and output frequency range of 15.625MHz to 250MHz. The reference divider, feedback divider and output divider are each programmable, thereby allowing for the following output- to-input frequency ratios: 8:1, 4:1, 2:1, 1:1, 1:2, 1:4, 1:8. The external feedback allows the device to achieve "zero delay" between the input clock and the output clocks. The PLL_SEL pin can be used to bypass the PLL for system test and debug purposes. In bypass mode, the reference clock is routed around the PLL and into the internal output dividers.


  • Eight LVCMOS/LVTTL outputs, 7Ω typical output impedance
  • Selectable CLK1, nCLK1 or LVCMOS/LVTTL clock inputs
  • CLK1, nCLK1 pair can accept the following differential input levels: LVPECL, LVDS, LVHSTL, HCSLSSTL
  • CLK0 input accepts LVCMOS or LVTTL input levels
  • Output frequency range: 15.625MHz to 250MHz
  • Input frequency range: 15.625MHz to 250MHz
  • VCO range: 250MHz to 500MHz
  • External feedback for “zero delay” clock regeneration with configurable frequencies
  • Programmable dividers allow for the following output-to-input frequency ratios: 8:1, 4:1, 2:1, 1:1, 1:2, 1:4, 1:8
  • Fully integrated PLL
  • Cycle-to-cycle jitter: 45ps (maximum)
  • Output skew: CLK0, 65ps (maximum) CLK1, nCLK1, 55ps (maximum)
  • Static Phase Offset: 25 ±125ps (maximum), CLK0
  • Full 3.3V or 2.5V operating supply
  • Lead-Free package available
  • -40°C to 85°C ambient operating temperature

Product Specification

Outputs (#)Output TypeOutput Freq Range (MHz)Input Freq (MHz)Inputs (#)Input TypeOutput Banks (#)Core Voltage (V)Output Voltage (V)
8LVCMOS15.625000 - 250.00000015.625000 - 250.0000002LVCMOS, HSTL, LVDS, LVPECL, SSTL, HCSL12.5, 3.32.5, 3.3

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
8705BYILFActivePRG32TQFP32IYesTrayCheck Availability
8705BYILFTActivePRG32TQFP32IYesReelCheck Availability


Technical Documentation

Title Other Languages Type Format File Size Datesort icon
Datasheets & Errata
8705I Datasheet Datasheet PDF 270 KB Jul 13, 2015
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 (12)
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-834 Hot-Swap Recommendations Application Note PDF 67 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-833 Differential Input Self Oscillation Prevention Application Note PDF 94 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
PCN# : TB1504-01R1 Qty per Reel Standardization for Selective Packages Product Change Notice PDF 95 KB Oct 22, 2015
show all (6)
PCN# : TB1504-01 Qty per Reel Standardization for Selective Packages Product Change Notice PDF 50 KB Jul 21, 2015
PCN# : A1401-02 Alternate Copper Wire Assembly Site Product Change Notice PDF 36 KB Feb 16, 2014
PCN# : TB1303-01 Change of Carrier Tape for TQFP-32, TQFP-48 Product Change Notice PDF 472 KB Mar 31, 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