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601-21 - Block Diagram
601-21 - Pinout


Low Phase Noise Clock Multiplier


The ICS601-21 is a low-cost, low phase noise, high performance clock synthesizer for applications which require low phase noise and low jitter. It is IDT’s lowestphase noise multiplier. Using IDT’s patented analog and digital Phase Locked Loop (PLL) techniques, the chip accepts a crystal or clock input, and produces output clocksup to 230 MHz at 3.3 V. This product is intended for clock generation. It has low output jitter (variation in the output period), but input to output skew and jitter are not defined nor guaranteed.



  • Fully integrated PLL, no external loop filter required 
  • Differential 3.3 V LVPECL outputs
  • Uses fundamental crystal or clock
  • Crystal input frequency: 10 to 27MHz
  • Clock input: 10 to 38MHz (mulitply by 6)
  • 0 to 31MHz (all other multiply settings)
  • Output clocks up to 230 MHz at 3.3 V
  • Low phase noise: -122 dBc/Hz at 10 kHz
  • Low jitter - 15 ps one sigma typ.
  • Powerdown mode lowers power consumption
  • Packaged in 16-pin TSSOP, Pb-free 
  • Advanced, low power, sub-micron CMOS process
  • Operating voltage of 3.3 V
  • Commercial temperature range available

Product Specification

Outputs (#)Output TypeOutput Freq Range (MHz)Inputs (#)Input TypeInput Freq (MHz)Output Voltage (V)Output Banks (#)Phase Jitter Typ RMS (ps)
1LVPECL10.000000 - 220.0000001LVCMOS, Crystal10.000000 - 27.0000003.31

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
601G-21LFLast Time BuyPGG16TSSOP16CYesTubeCheck Availability
601G-21LFTLast Time BuyPGG16TSSOP16CYesReelCheck Availability


Technical Documentation

Title Type Format File Size Datesort icon
Datasheets & Errata
601-21 Datasheet Datasheet PDF 94 KB Dec 14, 2012
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-844 Termination - AC Coupling Clock Receivers Application Note PDF 82 KB May 13, 2014
show all (18)
AN-842 Thermal Considerations in Package Design and Selection Application Note PDF 403 KB May 12, 2014
AN-803 Crystal Timing Budget and Accuracy for IDT Timing Clock Products Application Note PDF 44 KB May 8, 2014
AN-840 Jitter Specifications for Timing Signals Application Note PDF 349 KB May 8, 2014
AN-838 Peak-to-Peak Jitter Calculations Application Note PDF 32 KB May 7, 2014
AN-839 RMS Phase Jitter Application Note PDF 149 KB May 7, 2014
AN-832 Timing Budget and Accuracy Application Note PDF 48 KB May 6, 2014
AN-834 Hot-Swap Recommendations Application Note PDF 67 KB May 6, 2014
AN-830 Quartz Crystal Drive Level Application Note PDF 59 KB May 5, 2014
AN-815 Understanding Jitter Units Application Note PDF 476 KB Apr 24, 2014
AN-827 Application Relevance of Clock Jitter Application Note PDF 1.06 MB Apr 24, 2014
AN-802 Crystal-Measuring Oscillator Negative Resistance Application Note PDF 52 KB Mar 12, 2014
AN-806 Power Supply Noise Rejection Application Note PDF 353 KB Jan 15, 2014
AN-805 Recommended Ferrite Beads Application Note PDF 38 KB Jan 15, 2014
AN-801 Crystal-High Drive Level Application Note PDF 109 KB Jan 15, 2014
601-21 Demo Board Instructions Application Note PDF 1 KB Mar 9, 2006
PDN# : CQ-15-05 Market Declined Quarterly PDN Product Discontinuation Notice PDF 623 KB Oct 29, 2015
PCN# : TB1403-01 Changed in Carrier Tape, Plastic Reel and Quantity per Reel on TSSOP-14, TSSOP-16 Product Change Notice PDF 663 KB Apr 8, 2014
PCN# : TB1303-02 Change of Tape & Reel Packing Method for Selective Products Product Change Notice PDF 361 KB Mar 24, 2013
show all (4)
PCN# : A1208-01R1 Gold to Copper Wire Product Change Notice PDF 254 KB Dec 21, 2012