Skip to main content
83940 - Block Diagram
83940 - Pinout


Low Skew,1-to-18 LVPECL-to-LVCMOS/LVTTL Fanout Buffer

Alternative Products
NOTICE - The following device(s) are recommended alternatives:
Pin-to-pin compatible

The 83940 is a low skew, 1-to-18 LVPECL-to-LVCMOS/ LVTTL Fanout Buffer. The 83940 has twoselectable clock inputs. The PCLK, nPCLK pair can accept LVPECL, CML, or SSTL input levels. The LVCMOS_CLK can accept LVCMOS or LVTTL input levels. The low impedance LVCMOS/LVTTL outputs are designed to drive 50Ω series or parallel terminated transmission lines. The 83940 is characterized at full 3.3V, full 2.5V and mixed 3.3V input and 2.5V output operating supply modes. Guaranteed output and part-to-part skew characteristics make the 83940 ideal for those clock distribution applications demanding well defined performance and repeatability.


  • Eighteen LVCMOS/LVTTL outputs, 16Ω typical output impedance
  • Selectable LVCMOS_CLK or LVPECL clock inputs
  • PCLK, nPCLK supports the following input types: LVPECL, CMLSSTL
  • LVCMOS_CLK accepts the following input levels: LVCMOS or LVTTL
  • Maximum output frequency: 250MHz
  • Output skew: 150ps (maximum)
  • Part to part skew: 750ps (maximum)
  • Full 3.3V or 2.5V supply modes
  • 0°C to 70°C ambient operating temperature
  • Industrial temperature information available upon request
  • Lead-Free package fully RoHS compliant
  • NRND - Not Recommended for New Designs 
  • For new designs use 83940D

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)
18LVCMOS0.000000 - 250.0000000.000000 - 250.0000002LVCMOS, LVPECL, SSTL, CML12.5, 3.3150

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
83940BYLFObsoletePRG32TQFP32CYesTrayCheck Availability
83940BYLFTObsoletePRG32TQFP32CYesReelCheck 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-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-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-833 Differential Input Self Oscillation Prevention Application Note PDF 94 KB May 6, 2014
AN-836 Differential Input to Accept Single-ended Levels Application Note PDF 37 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-14-02R2 Product Discontinuation Notice PDF 549 KB Aug 4, 2014
PCN# : A1401-02 Alternate Copper Wire Assembly Site Product Change Notice PDF 36 KB Feb 16, 2014
PDN# : CQ-14-02R1 PRODUCT DISCONTINUANCE NOTICE Product Discontinuation Notice PDF 545 KB Feb 11, 2014
show all (6)
PDN# : CQ-14-02 PRODUCT DISCONTINUANCE NOTICE Product Discontinuation Notice PDF 544 KB Jan 26, 2014
PCN# : A1309-01 Changed of Traceability Mark Format Product Change Notice PDF 439 KB Oct 11, 2013
PCN# : TB1303-01 Change of Carrier Tape for TQFP-32, TQFP-48 Product Change Notice PDF 472 KB Mar 31, 2013
IDT Clock Distribution Overview 日本語 Overview PDF 3.79 MB Apr 25, 2016