The 9EX21531 provides 15 output clocks for PCIe Gen1/ 2/3 applications. The 9EX21531 has 4 selectable SMBus addresses, and dedicated CKPWRGD/PD# and VDDA pins for easy board design. A differential clock from a CK410B+ or CK420BQ main clock generator, such as the 932S421, drives the 9EX21531. In fanout mode, the 9EX21531 provides outputs up to 166MHz.


  • 15 - 0.7V current mode differential HSCL output pairs
  • Pin compatible to 9EX21501/ Easy PCIe Gen3 upgrade
  • 4 Selectable SMBus Addresses/Mulitple devices can share the same SMBus Segment
  • 8 dedicated and 2 group OE# pins/Hardware control of the outputs
  • PLL or bypass mode/PLL can dejitter incoming clock
  • Selectable PLL bandwidth/minimizes jitter peaking in downstream PLL's
  • Spread Spectrum Compatible/tracks spreading input clock for low EMI
  • SMBus Interface/unused outputs can be disabled
  • Undriven differential outputs in Power Down mode/ Easy power management
  • Cycle-to-cycle jitter <50ps
  • Output-to-output skew < 150 ps
  • PCIe Gen3 phase jitter < 1.0ps RMS

Product Options

Orderable Part ID Part Status Pkg. Code Pkg. Type Lead Count (#) Temp. Grade Pb (Lead) Free Carrier Type Buy Sample
9EX21531AKLF Obsolete NLG64P2 VFQFPN 64 C Yes Tray
9EX21531AKLFT Obsolete NLG64P2 VFQFPN 64 C Yes Reel

Technical Documentation

Title Other Languages Type Format File Size Date
Datasheets & Errata
9EX21531 Datasheet Datasheet PDF 221 KB
Application Notes & White Papers
AN-828 Termination - LVPECL Application Note PDF 229 KB
AN-844 Termination - AC Coupling Clock Receivers Application Note PDF 82 KB
AN-843 PCI Express Reference Clock Requirements Application Note PDF 1.81 MB
AN-842 Thermal Considerations in Package Design and Selection Application Note PDF 403 KB
AN-835 Differential Input with VCMR being VIH Referenced Application Note PDF 77 KB
AN-840 Jitter Specifications for Timing Signals Application Note PDF 349 KB
AN-836 Differential Input to Accept Single-ended Levels Application Note PDF 37 KB
AN-827 Application Relevance of Clock Jitter Application Note PDF 1.06 MB
AN-815 Understanding Jitter Units Application Note PDF 476 KB
AN-805 Recommended Ferrite Beads Application Note PDF 38 KB
PDN# : CQ-17-04(R1) Product Discontinuance Notice Product Discontinuation Notice PDF 606 KB
PDN# : CQ-17-04 Product Discontinuance Notice Product Discontinuation Notice PDF 599 KB
PCN# : A1611-02 Add JCET China as Alternate Assembly and Change of Material Set at Alternate Assembly Location Product Change Notice PDF 583 KB
PCN# : TB1504-01R1 Qty per Reel Standardization for Selective Packages Product Change Notice PDF 95 KB
PCN# : TB1504-01 Qty per Reel Standardization for Selective Packages Product Change Notice PDF 50 KB
Timing Solutions Products Overview Overview PDF 4.11 MB
PCI Express® Timing Solutions Overview Overview PDF 301 KB
IDT Clock Generation Overview 日本語 Overview PDF 1.83 MB
IDT Clock Distribution Overview 日本語 Overview PDF 3.79 MB