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813253 - Block Diagram
813253 - Pinout


Femtoclock® Jitter Attenuator & Multiplier Frequency Translator W/LVPECL Outputs

Alternative Products
NOTICE - The following device(s) are recommended alternatives:
Functionally compatible
Functionally compatible

The 813253 is a PLL based synchronous clock generator that is optimized for Gigabit Ethernet and PCI Express®™ clock jitter attenuation and frequency translation. The device contains two internal frequency multiplication stages that are cascaded in series. The first stage is a VCXO PLL that is optimized to provide reference clock jitter attenuation. The second stage is a FemtoClock® frequency multiplier that provides the low jitter, high frequency Gigabit Ethernet or PCI Express®™ output clock. Pre-divider and output divider multiplication ratios are selected using device selection control pins. The multiplication ratios are optimized to support most common clock rates used in Gigabit Ethernet and PCI Express® applications. The VCXO requires the use of an external, inexpensive pullable crystal. The VCXO uses external passive loop filter components which allows configuration of the PLL loop bandwidth and damping characteristics.


  • Three differential LVPECL output pairs
  • One differential input supports the following input types: LVPECL, LVDS, LVHSTLHCSL
  • Accepts input frequencies from 19.6MHz to 136MHz, including: 25MHz, 62.5MHz, 100MHz and 125MHz input clocks
  • Attenuates the phase jitter of the input clock by using a low-cost fundamental mode VCXO crystal
  • Outputs common Gigabit Ethernet or PCI Express® clock rates
  • VCXO PLL bandwidth can be optimized for jitter attenuation and reference tracking using external loop filter connection
  • Absolute pull range: ±50ppm
  • FemtoClock frequency multiplier provides low jitter, high frequency output
  • FemtoClock VCO range: 490MHz - 680MHz
  • RMS phase jitter @ 156.25MHz, using a 25MHz crystal (1.875MHz – 20MHz): 0.421ps (typical)
  • Full 3.3V supply, or mixed 3.3V core 2.5V output supply
  • 0°C to 70°C ambient operating temperature
  • Available in lead-free (RoHS 6) package

Product Specification

Outputs (#)Output TypeOutput Freq Range (MHz)Input Freq (MHz)Inputs (#)Input TypeOutput Banks (#)Core Voltage (V)Output Voltage (V)Output Skew (ps)Phase Jitter Typ RMS (ps)Phase Jitter Max RMS (ps)
3LVPECL98.000000 - 170.000000, 245.000000 - 340.000000, 19.600000 - 27.20000049.000000 - 68.000000, 78.400000 - 136.000000, 19.600000 - 27.2000001LVDS, HCSL, HSTL, LVPECL13.32.5, 3.3350.421

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
813253BGLFObsoletePGG24TSSOP24CYesTubeCheck Availability
813253BGLFTObsoletePGG24TSSOP24CYesReelCheck Availability


Technical Documentation

Title Type Format File Size Datesort icon
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-842 Thermal Considerations in Package Design and Selection Application Note PDF 403 KB May 12, 2014
show all (15)
AN-840 Jitter Specifications for Timing Signals Application Note PDF 349 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-836 Differential Input to Accept Single-ended Levels Application Note PDF 37 KB May 6, 2014
AN-835 Differential Input with VCMR being VIH Referenced Application Note PDF 77 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-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
AN-806 Power Supply Noise Rejection Application Note PDF 353 KB Jan 15, 2014
PDN# : CQ-14-03 Quarter PDN for Declined Market Product Discontinuation Notice PDF 539 KB Apr 25, 2014