NOTICE - The following device(s) are recommended alternatives:
9ZXL1251E - 12-Output DB1200ZL PCIe Clock Clock Buffer
Pin-to-pin with improved performance

The 9ZXL1251 meets the demanding requirements of the Intel DB1200ZL specification, including the critical low-drift requirements of Intel CPUs. It is pin  compatible to the 9ZXL1231 and integrates 24 termination resistors, saving 41mm² board area.


  • 85Ω Low-power push-pull HCSL outputs; eliminate 24 resistors, save 41mm² of area
  • Pin compatible to 9ZX21201 and 9ZXL1231; easy path to power and area savings
  • Space-saving 64-pin VFQFPN package
  • Fixed feedback path for 0 ps input-to-output delay
  • 9 Selectable SMBus Addresses; multiple devices can share the same SMBus Segment
  • 12 OE# pins; hardware control of each output
  • PLL or bypass mode; supports common and separate clock architectures
  • Selectable PLL bandwidth; minimizes jitter peaking in downstream PLL's
  • Spread Spectrum Compatible; tracks spreading input clock for low EMI
  • -40°C to +85°C device available; supports demanding environmental applications

Product Options

Orderable Part ID Part Status Pkg. Type Lead Count (#) Temp. Grade Pb (Lead) Free Carrier Type Package Buy Sample
9ZXL1251AKILF Active VFQFPN 64 I 1 Tray Package Info
9ZXL1251AKILFT Active VFQFPN 64 I 1 Reel Package Info
9ZXL1251AKLF Active VFQFPN 64 C 1 Tray Package Info
9ZXL1251AKLFT Active VFQFPN 64 C 1 Reel Package Info

Documentation & Downloads

Title Other Languages Type Format File Size Date
Datasheets & Errata
9ZXL1251 Datasheet Datasheet PDF 467 KB
Application Notes & White Papers
AN-975 Cascading PLLs Application Note PDF 255 KB
AN-828 Termination - LVPECL Application Note PDF 322 KB
AN-891 Driving LVPECL, LVDS, CML, and SSTL Logic with IDT?s ?Universal? Low-Power HCSL Outputs Application Note PDF 480 KB
AN-879 Low-Power HCSL vs Traditional HCSL Application Note PDF 235 KB
AN-844 Termination - AC Coupling Clock Receivers Application Note PDF 170 KB
AN-842 Thermal Considerations in Package Design and Selection Application Note PDF 495 KB
AN-840 Jitter Specifications for Timing Signals Application Note PDF 442 KB
AN-827 Application Relevance of Clock Jitter Application Note PDF 1.15 MB
AN-815 Understanding Jitter Units Application Note PDF 565 KB
AN-808 PCI Express/HCSL Termination Application Note PDF 137 KB
AN-805 Recommended Ferrite Beads Application Note PDF 121 KB
PCN# : A1904-01 Add Greatek, Taiwan as an Alternate Assembly Facility Product Change Notice PDF 983 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
PCN# : A1403-03 Gold wire to Copper wire Product Change Notice PDF 42 KB
PCN# : A1311-03R1 Alternate Assembly Locations Product Change Notice PDF 43 KB
PCN# : A1311-03 Alternate Assembly Locations Product Change Notice PDF 140 KB
9ZXL1251 IBIS Model Model - IBIS ZIP 30 KB
PCI Express Timing Solutions Overview Overview PDF 275 KB
Timing Solutions Products Overview Overview PDF 4.11 MB
IDT Clock Generation Overview 日本語 Overview PDF 1.83 MB
IDT Clock Distribution Overview 日本語 Overview PDF 3.79 MB