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8535I-21 - Block Diagram
8535I-21 - Pinout


Low Skew,1-to-2 LVCMOS/LVTTL-to-3.3V LVPECL Clock Generator

The 8535I-21 is a low skew, high performance 1-to-2 LVCMOS/LVTTL-to-3.3V LVPECL fanout buffer and a member of the HiPerClockS™ family of High Performance Clock Solutions from IDT. The 8535I-21 has two single-ended clock inputs. The single-ended clock input accepts LVCMOS or LVTTL input levels and translate them to 3.3V LVPECL levels. The clock enable is internally synchronized to eliminate runt clock pulses on the output during asynchronous assertion/deassertion of the clock enable pin. Guaranteed output and part-to-part skew characteristics make the 8535I-21 ideal for those applications demanding well defined performance and repeatability.


  • Two differential 3.3V LVPECL outputs
  • Selectable CLK0 or CLK1 inputs for redundant and multiple frequency fanout applications
  • CLK0 or CLK1 can accept the following input levels: LVCMOS or LVTTL
  • Maximum output frequency: 266MHz
  • Translates LVCMOS and LVTTL levels to 3.3V LVPECL levels
  • Output skew: 20ps (maximum)
  • Part-to-part skew: 300ps (maximum)
  • Propagation delay: 1.6ns (maximum)
  • Additive phase jitter, RMS: 0.03ps (typical)
  • 3.3V operating supply
  • -40°C to 85°C ambient operating temperature
  • Available in lead-free (RoHS 6) package

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 (ps)
2LVPECL0.000000 - 266.0000000.000000 - 266.0000002LVCMOS13.3200.03

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
8535AGI-21LFActivePGG14TSSOP14IYesTubeCheck Availability
8535AGI-21LFTActivePGG14TSSOP14IYesReelCheck Availability


Technical Documentation

Title Other Languages Type Format File Size Datesort icon
Datasheets & Errata
ICS8535I-21 DATASHEET Datasheet PDF 756 KB Nov 24, 2008
Apps Notes & White Papers
AN-828 Termination - LVPECL Application Note PDF 229 KB Jul 5, 2016
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
show all (8)
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-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# : TB1403-01 Changed in Carrier Tape, Plastic Reel and Quantity per Reel on TSSOP-14, TSSOP-16 Product Change Notice PDF 663 KB Apr 8, 2014
show all (5)
PCN# : A1309-01 Changed of Traceability Mark Format Product Change Notice PDF 439 KB Oct 11, 2013
PCN# : TB1303-02 Change of Tape & Reel Packing Method for Selective Products Product Change Notice PDF 361 KB Mar 24, 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