Field Programmable SS VersaClock Synthesizer

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

The 251 is a low cost, single-output, field programmable clock synthesizer. The 251 can generate an output frequency from 314 kHz to 200 MHz and may employ Spread Spectrum techniques to reduce system electro-magnetic interference (EMI). Using IDT's VersaClock™ software to configure the PLL and output, the 251 contains a One-Time Programmable (OTP) ROM to allow field programmability. Programming features include 4 selectable configuration registers. The device employs Phase-Locked Loop (PLL) techniques to run from a standard fundamental mode, inexpensive crystal, or clock. It can replace multiple crystals and oscillators, saving board space and cost. The device also has a power-down feature that tri-states the clock outputs and turns off the PLLs when the PDTS pin is taken low. The 251 is also available in factory programmed custom versions for high-volume applications.

Features

  • 8-pin SOIC package
  • Four addressable registers
  • Input crystal frequency of 5 to 27 MHz
  • Clock input frequency of 3 to 150 MHz
  • Output clock frequencies up to 200 MHz
  • Configurable Spread Spectrum Modulation
  • Operating voltage of 3.3 V
  • Replaces multiple crystals and oscillators
  • Controllable output drive levels
  • Advanced, low-power CMOS process
  • Available in RoHS compliant packaging

Product Options

Orderable Part ID Part Status Pkg. Code Pkg. Type Lead Count (#) Temp. Grade Pb (Lead) Free Carrier Type Buy Sample
251PMILF Active DCG8 SOIC 8 I Yes Tube Availability
251PMLF Active DCG8 SOIC 8 C Yes Tube Availability

Technical Documentation

Title Other Languages Type Format File Size Date
Datasheets & Errata
251 Datasheet Datasheet PDF 131 KB Oct 11, 2017
User Guides & Manuals
VersaClock II User Guide Manual Manual - User Reference PDF 612 KB Feb 6, 2012
Application Notes & White Papers
AN-828 Termination - LVPECL Application Note PDF 229 KB Jul 5, 2016
AN-835 Differential Input with VCMR being VIH Referenced Application Note PDF 77 KB May 10, 2014
AN-815 Understanding Jitter Units Application Note PDF 476 KB Apr 23, 2014
AN-831 The Crystal Load curve Application Note PDF 308 KB Sep 22, 2014
AN-845 Termination - LVCMOS Application Note PDF 62 KB May 12, 2014
AN-844 Termination - AC Coupling Clock Receivers Application Note PDF 82 KB May 12, 2014
AN-842 Thermal Considerations in Package Design and Selection Application Note PDF 403 KB May 11, 2014
AN-803 Crystal Timing Budget and Accuracy for IDT Timing Clock Products Application Note PDF 44 KB May 7, 2014
AN-840 Jitter Specifications for Timing Signals Application Note PDF 349 KB May 7, 2014
AN-839 RMS Phase Jitter Application Note PDF 149 KB May 6, 2014
AN-838 Peak-to-Peak Jitter Calculations Application Note PDF 32 KB May 6, 2014
AN-837 Overdriving the Crystal Interface Application Note PDF 50 KB May 5, 2014
AN-836 Differential Input to Accept Single-ended Levels Application Note PDF 37 KB May 5, 2014
AN-834 Hot-Swap Recommendations Application Note PDF 67 KB May 5, 2014
AN-832 Timing Budget and Accuracy Application Note PDF 48 KB May 5, 2014
AN-830 Quartz Crystal Drive Level Application Note PDF 59 KB May 4, 2014
AN-802 Crystal-Measuring Oscillator Negative Resistance Application Note PDF 52 KB Mar 11, 2014
AN-827 Application Relevance of Clock Jitter Application Note PDF 1.06 MB Apr 23, 2014
AN-806 Power Supply Noise Rejection Application Note PDF 353 KB Jan 14, 2014
AN-805 Recommended Ferrite Beads Application Note PDF 38 KB Jan 14, 2014
AN-801 Crystal-High Drive Level Application Note PDF 109 KB Jan 14, 2014
PCNs & PDNs
PCN# : A1602-01(R1) Add Greatek Taiwan as Alternate Assembly Product Change Notice PDF 611 KB Apr 13, 2016
PCN# : A1602-01 Add Greatek Taiwan as Alternate Assembly Product Change Notice PDF 611 KB Feb 14, 2016
PDN# : U-11-05R1 PRODUCT DISCONTINUANCE NOTICE FOR SELECTIVE MICRO CLOCK DEVICES Product Delete Notice PDF 71 KB May 17, 2011
PDN# : U-11-05 PRODUCT DISCONTINUANCE NOTICE FOR SELECTIVE MICRO CLOCK DEVICES Product Delete Notice PDF 70 KB May 3, 2011
Other
The IDT Communications Products Advantage Overview PDF 2.54 MB Feb 13, 2017
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 24, 2016

Software & Tools

Title Other Languages Type Format File Size Date
VersaClock II Desktop Software Setup Software ZIP 6.24 MB Feb 6, 2012

News & Additional Resources