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87946I-147 - Block Diagram
87946I-147 - Pinout


1-to-10 Low Skew,÷1,÷2 LVCMOS/LVTTL 2.5V, 3.3V Fanout Buffer

The 87946I-147 is a low skew, ÷1, ÷2 LVCMOS/LVTTL Fanout Buffer. The 87946I-147 has two selectable single-ended clock inputs. The single-ended clock inputs accept LVCMOS or LVTTL input levels. The low impedance LVCMOS/LVTTL outputs are designed to drive 50Ω series or parallel terminated transmission lines. The effective fanout can be increased from 10 to 20 by utilizing the ability of the outputs to drive two series terminated lines.

The divide select inputs, DIV_SELx, control the output frequency of each bank. The outputs can be utilized in the ÷1, ÷2 or a combination of ÷1 and ÷2 modes. The master reset input, MR/nOE, resets the internal frequency dividers and also controls the active and high impedance states of all outputs.

The 87946I-147 is characterized at full 3.3V for input VDD, and mixed 3.3V and 2.5V for output operating supply mode. Guaranteed bank, output and part-to-part skew characteristics make the 87946I-147 ideal for those clock distribution applications demanding well defined performance and repeatability.


  • Ten single-ended LVCMOS/LVTTL outputs, 7Ω typical output impedance
  • Selectable LVCMOS/LVTTL CLK0 and CLK1 inputs
  • CLK0 and CLK1 can accept the following input levels: LVCMOS and LVTTL
  • Maximum input frequency: 250MHz
  • Bank skew: 30ps (maximum)
  • Output skew: 175ps (maximum)
  • Part-to-part skew: 850ps (maximum)
  • Multiple frequency skew: 200ps (maximum)
  • 3.3V core, 3.3V or 2.5V output supply modes
  • -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 Voltage (V)Divider ValueOutput Skew (ps)Additive Phase Jitter Typ RMS (ps)
10LVCMOS0.000000 - 250.0000000.000000 - 250.0000002LVCMOS33.32.5, 3.31, 2175

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
87946AYI-147LFActivePRG32TQFP32IYesTrayCheck Availability
87946AYI-147LF/WActivePRG32TQFP32IYesReelCheck Availability
87946AYI-147LFTActivePRG32TQFP32IYesReelCheck Availability


Technical Documentation

Title Other Languages Type Format File Size Datesort icon
Datasheets & Errata
87946I-147 Final Datasheet Datasheet PDF 201 KB Sep 19, 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 (9)
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-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
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 (8)
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
PDN# : N-12-22R2 PRODUCT DISCONTINUANCE NOTICE Product Discontinuation Notice PDF 363 KB Jun 14, 2013
PCN# : TB1303-01 Change of Carrier Tape for TQFP-32, TQFP-48 Product Change Notice PDF 472 KB Mar 31, 2013
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
87946I-147 IBIS Model - IBIS ZIP 69 KB Nov 4, 2009