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

The 873991-147 is a low voltage, low skew, 3.3V LVPECL or ECL Clock Generator and a member of the family of High Performance Clock Solutions from IDT. The 873991-147 has two selectable clock inputs. The CLK, nCLK pair can accept LVPECL, LVDS, LVHSTL, SSTL and HCSL input levels and, the REF_CLK pin can accept a LVCMOS or LVTTL input levels. This device has a fully integrated PLL along with frequency configurable outputs. An external feedback input and output regenerates clocks with "zero delay". The four independent banks of outputs each have their own output dividers, which allow the device to generate a multitude of different bank frequency ratios and output-to-input frequency ratios. The output frequency range is 25MHz to 480MHz and the input frequency range is 6.25MHz to 120MHz. The PLL_EN input can be used to bypass the PLL for test and system debug purposes. In bypass mode, the input clock is routed around the PLL and into the internal output dividers. The 873991-147 also has a SYNC output which can be used for system synchronization purposes. It monitors Bank A and Bank C outputs for coincident rising edges and signals a pulse per the timing diagrams in this data sheet. This feature is used primarily in applications where Bank A and Bank C are running at different frequencies, and is particularly useful when they are running at non-integer multiples of each other.


  • Fourteen differential 3.3V LVPECL/ECL outputs
  • Selectable differential or REF_CLK inputs
  • CLK, nCLK can accept the following input levels: LVPECL, LVDS, LVHSTL, SSTL, HCSL
  • REF_CLK accepts the following input levels: LVCMOS, LVTTL
  • Input clock frequency range: 6.25MHz to 120MHz
  • Maximum output frequency: 480MHz
  • VCO range: 200MHz to 960MHz
  • Output skew: 250ps (maximum), outputs at the same frequency
  • Cycle-to-cycle jitter: 55ps (maximum)
  • LVPECL mode operating voltage supply range: VCC = 3.135V to 3.465V, VEE = 0V
  • ECL mode operating voltage supply range: VCC = 0V, VEE = -3.465V to -3.135V
  • 0°C to 50°C ambient operating temperature
  • Available in lead-free (RoHS 6) package

Product Options

Orderable Part ID Part Status Type Lead Count (#) Temp. Grade Pb (Lead) Free Carrier Type Buy Sample
Obsolete 52 C Yes Tray
Obsolete 52 C Yes Reel

Documentation & Downloads

Title Other Languages Type Format File Size Date
Datasheets & Errata
873991-147 Datasheet Datasheet PDF 422 KB
Application Notes & White Papers
AN-828 Termination - LVPECL Application Note PDF 322 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-833 Differential Input Self Oscillation Prevention Application Note PDF 180 KB
AN-834 Hot-Swap Recommendations Application Note PDF 153 KB
AN-836 Differential Input to Accept Single-ended Levels Application Note PDF 120 KB
AN-835 Differential Input with VCMR being VIH Referenced Application Note PDF 160 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-805 Recommended Ferrite Beads Application Note PDF 121 KB
PDN# : CQ-15-04 Quarterly Market Declined PDN Product Discontinuation Notice PDF 545 KB
PCN# : A1401-02 Alternate Copper Wire Assembly Site Product Change Notice PDF 36 KB
PCN#: A1309-03 Additional Assembly Sources Product Change Notice PDF 398 KB
873991-147 IBIS Model Model - IBIS ZIP 35 KB
Clock Distribution Overview 日本語 Overview PDF 217 KB
Timing Solutions Products Overview Overview PDF 4.11 MB
IDT Clock Generation Overview 日本語 Overview PDF 1.83 MB