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841484I - Block Diagram
841484I - Pinout


FemtoClock® Crystal-to-0.7V Differential

The 841484I is an optimized PCIe and sRIO clock generator. The device uses a 25MHz parallel resonant crystal to generate 100MHz, 125MHz, 200MHz and 400MHz clock signals, replacing solutions requiring multiple oscillator and fanout buffer solutions. The device has excellent phase jitter suitable to clock components requiring precise and low jitter PCIe, sRIO or both clock signals. The device also supports a configurable spread-spectrum generation for PCIe applications. Designed for telecom, networking and industrial applications, the 841484I can also drive the high-speed sRIO and PCIe SerDes clock inputs of communications processors, DSPs, switches and bridges.


  • Four 0.7V differential HCSL outputs: configurable for PCIe (100MHz or 200MHz) and sRIO (125MHz) clock signals
  • One LVCMOS/LVTTL reference clock output
  • Selectable crystal oscillator interface, 25MHz, 18pF parallel resonant crystal or LVCMOS/LVTTL single-ended reference clock input
  • Supports the following output frequencies: 100MHz, 125MHz, 200MHz or 400MHz
  • VCO frequency range: 950MHz - 1.25GHz
  • Configurable spread-spectrum generation for PCIe
  • PLL bypass and output enable
  • RMS phase jitter @ 200MHz, using a 25MHz crystal (12kHz - 20MHz): 1.21ps (typical)
  • PCI Express (2.5 Gb/S), Gen 2 (5 Gb/s) and Gen 3 (8 Gb/s) jitter compliant (REF_OUT disabled)
  • Full 3.3V operating supply
  • -40°C to 85°C ambient operating temperature
  • Available in lead-free (RoHS 6) packages

Product Specification

Output TypeOutput Freq Range (MHz)Input Freq (MHz)Inputs (#)Input TypeOutput Banks (#)Core Voltage (V)Output Voltage (V)
LVCMOS, HCSL25.000000, 100.000000, 125.000000, 200.000000, 400.00000025.0000002LVCMOS, Crystal23.33.3

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
841484DKILFActiveNLG32P3VFQFPN32IYesTrayCheck Availability
841484DKILFTActiveNLG32P3VFQFPN32IYesReelCheck Availability


Technical Documentation

Title Other Languages Type Format File Size Datesort icon
Datasheets & Errata
841484I Datasheet Datasheet PDF 803 KB Nov 14, 2012
PCN# : A1511-01(R1) Add SPEL India as Alternate Assembly Location Product Change Notice PDF 596 KB Jan 28, 2016
PCN# : A1511-01 Add SPEL India as Alternate Assembly Location Product Change Notice PDF 544 KB Nov 13, 2015
IDT PCI Express Solutions Overview 简体中文, 日本語 Overview PDF 945 KB Aug 4, 2016
IDT Clock Generation Overview 日本語 Overview PDF 1.83 MB Apr 28, 2016
IDT Clock Distribution Overview 日本語 Overview PDF 3.79 MB Apr 25, 2016

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