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843241 - Block Diagram
843241 - Pinout


FemtoClock® SAS/SATA Clock Generator

The 843241 is a low jitter, high performance clock generator and a member of the FemtoClock® family of silicon timing products. The 843241 is designed for use in the SAS-2 interconnect and the three transport protocols that use the SAS-2 interconnect: Serial SCSI Protocol (SSP), Serial ATA Tunneled Protocol (STP), and Serial Management Protocol (SMP). The 843241 has excellent (<1ps) RMS phase jitter, over the SAS defined integration range. The 843241 uses an external, 25MHz, parallel resonant crystal to generate three selectable output frequencies: 75MHz, 100MHz, 150MHz, and 300MHz. This silicon based approach provides excellent frequency stability and reliability. The 843241 features up, down, and center spread spectrum (SSC) clocking techniques. The up, down and center SSC will be required in the SAS-2 applications that have three clock trees in the HBA and expander ASICs (see Applications Information section, Figure 3).


  • Designed for use in SAS-2 systems
  • Up, down and center spread spectrum clocking
  • One differential 3.3V or 2.5V LVPECL output pair
  • Selectable output frequencies: 75MHz, 100MHz, 150MHz, 300MHz
  • RMS phase jitter @ 75MHz, (900kHz – 7.5MHz): 0.70ps (typical)
  • 3.3V or 2.5V operating supply
  • 0°C to 70°C ambient operating temperature
  • Available in lead-free (RoHS 6) packages

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
843241BM-100LFActiveDCG8SOIC8CYesTubeCheck Availability
843241BM-100LFTActiveDCG8SOIC8CYesReelCheck Availability
843241BM-150LFActiveDCG8SOIC8CYesTubeCheck Availability
843241BM-150LFTActiveDCG8SOIC8CYesReelCheck Availability
843241BM-300LFActiveDCG8SOIC8CYesTubeCheck Availability
843241BM-300LFTActiveDCG8SOIC8CYesReelCheck Availability
843241BM-75LFActiveDCG8SOIC8CYesTubeCheck Availability
843241BM-75LFTActiveDCG8SOIC8CYesReelCheck Availability


Technical Documentation

Title Type Format File Size Datesort icon
Datasheets & Errata
843241 Data Sheet Datasheet PDF 445 KB Apr 4, 2014
Apps Notes & White Papers
AN-828 Termination - LVPECL Application Note PDF 229 KB Jul 5, 2016
AN-831 The Crystal Load curve Application Note PDF 308 KB Sep 22, 2014
AN-844 Termination - AC Coupling Clock Receivers Application Note PDF 82 KB May 13, 2014
show all (18)
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-803 Crystal Timing Budget and Accuracy for IDT Timing Clock Products Application Note PDF 44 KB May 8, 2014
AN-839 RMS Phase Jitter Application Note PDF 149 KB May 7, 2014
AN-838 Peak-to-Peak Jitter Calculations Application Note PDF 32 KB May 7, 2014
AN-837 Overdriving the Crystal Interface Application Note PDF 50 KB May 6, 2014
AN-834 Hot-Swap Recommendations Application Note PDF 67 KB May 6, 2014
AN-832 Timing Budget and Accuracy Application Note PDF 48 KB May 6, 2014
AN-830 Quartz Crystal Drive Level Application Note PDF 59 KB May 5, 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-802 Crystal-Measuring Oscillator Negative Resistance Application Note PDF 52 KB Mar 12, 2014
AN-806 Power Supply Noise Rejection Application Note PDF 353 KB Jan 15, 2014
AN-801 Crystal-High Drive Level Application Note PDF 109 KB Jan 15, 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 (5)
PCN# : TB1504-01 Qty per Reel Standardization for Selective Packages Product Change Notice PDF 50 KB Jul 21, 2015
PCN# : TB1303-02 Change of Tape & Reel Packing Method for Selective Products Product Change Notice PDF 361 KB Mar 24, 2013