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87949I - Block Diagram
87949I - Pinout


Low Skew,1,÷2 Clock Generator

Alternative Products
NOTICE - The following device(s) are recommended alternatives:

The 87949I is a low skew, ÷1, ÷2 Clock Generator. The 87949I has selectable single ended clock or LVPECL clock inputs. The single ended clock input accepts LVCMOS or LVTTL input levels. The PCLK, nPCLK pair can accept LVPECL, CML, or SSTL input levels. The low impedance LVCMOS outputs are designed to drive 50? series or parallel terminated transmission lines.The effective fanout can be increased from 15 to 30 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 87949I is characterized at 3.3V core/3.3V output. Guaranteed output and part-to-part skew characteristics make the 87949I ideal for those clock distribution applications demanding well defined performance and repeatability.


  • Fifteen single ended LVCMOS outputs, 7? typical output impedance
  • Selectable LVCMOS or LVPECL clock inputs
  • CLK0 and CLK1 can accept the following input levels: LVCMOS and LVTTL
  • PCLK, nPCLK supports the following input types: LVPECL, CMLSSTL
  • Maximum output frequency: 160MHz
  • Output skew: 350ps (maximum)
  • Part-to-part skew: 2.75ns (maximum)
  • 3.3V supply voltage
  • -40°C to 85°C ambient operating temperature
  • Available in lead-free RoHS compliant packages

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)
15LVCMOS0.000000 - 160.0000000.000000 - 160.0000003LVCMOS, LVPECL, SSTL, CML43.33.31, 2350

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
87949AYILFObsoletePPG52TQFP52IYesTrayCheck Availability
87949AYILFTObsoletePPG52TQFP52IYesReelCheck Availability


Technical Documentation

Title Other Languages Type Format File Size Datesort icon
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-845 Termination - LVCMOS Application Note PDF 62 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-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-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
PDN# : CQ-15-01 (R1) Quarter PDN for Declined Market Product Discontinuation Notice PDF 550 KB Mar 11, 2015
PDN# : CQ-15-01 Quarter PDN for Declined Market Product Discontinuation Notice PDF 547 KB Jan 23, 2015
PCN# : A1401-02 Alternate Copper Wire Assembly Site Product Change Notice PDF 36 KB Feb 16, 2014
show all (6)
PCN#: A1309-03 Additional Assembly Sources Product Change Notice PDF 398 KB Oct 21, 2013
PDN# : N-12-22R2 PRODUCT DISCONTINUANCE NOTICE Product Discontinuation Notice PDF 363 KB Jun 14, 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
87949I IBIS Model - IBIS ZIP 37 KB Nov 4, 2009