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

The 843034 is a general purpose, low phase noise LVPECL synthesizer which can generate frequencies for a wide variety of applications. The 843034 has a 4:1 input Multiplexer from which the following inputs can be selected: one differential input, one single-ended input, or two crystal oscillators, thus making the device ideal for frequency translation or frequency generation. Each differential LVPECL output pair has an output divider which can be independently set so that two different frequencies can be generated. Additionally, each LVPECL output pair has a dedicated power supply pin so the outputs can run at 3.3V or 2.5V. The 843034 also supplies a buffered copy of the reference clock or crystal frequency on the single-ended REF_CLK output pin which can be enabled or disabled (disabled by default). The output frequency can be programmed using either a serial or parallel programming interface. The phase jitter of the 843034 is less than 1ps rms, making it suitable for use in Fibre Channel, SONET, and Ethernet applications. Example applications include systems which must support both FEC and non FEC rates. In 10Gb Fibre Channel, for example, you can use a 25.5MHz crystal to generate a 159.375MHz reference clock, and then switch to a 20.544MHz crystal to generate 164.355MHz for 66/64 FEC. Other applications could include supporting both Ethernet frequencies and SONET frequencies in an application. When Ethernet frequencies are needed, a 25MHz crystal can be used and when SONET frequencies are needed, the input MUX can be switched to select a 38.88MHz crystal.


  • Dual differential 3.3V LVPECL outputs which can be set independently for either 3.3V or 2.5V
  • 4:1 Input Mux: One differential input One single-ended input Two crystal oscillator interfaces
  • CLK, nCLK pair can accept the following differential input levels: LVPECL, LVDS, LVHSTL, HCSL
  • TEST_CLK accepts LVCMOS or LVTTL input levels
  • Output frequency range: 35MHz to 625MHz
  • Crystal input frequency range: 12MHz to 40MHz
  • VCO range: 560MHz to 625MHz
  • Parallel or serial interface for programming feedback divider and output dividers
  • RMS phase jitter at 333.33MHz, using a 22.222MHz crystal (12kHz to 20MHz): 0.91ps (typical)
  • Supply voltage modes: LVPECL outputs (core/outputs): 3.3V/3.3V 3.3V/2.5V REF_CLK output (core/outputs): 3.3V/3.3V
  • 0°C to 70°C ambient operating temperature
  • Industrial temperature available upon request with E-pad option.
  • Available in lead-free (RoHS 6) packages

Product Options

Orderable Part ID Part Status Type Lead Count (#) Temp. Grade Pb (Lead) Free Carrier Type Buy Sample
Obsolete 48 C Yes Tray
Obsolete 48 C Yes Reel

Documentation & Downloads

Title Other Languages Type Format File Size Date
Datasheets & Errata
ICS843034 Datasheet Datasheet PDF 846 KB
Application Notes & White Papers
AN-828 Termination - LVPECL Application Note PDF 322 KB
AN-831 The Crystal Load curve Application Note PDF 395 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-803 Crystal Timing Budget and Accuracy for IDT Timing Clock Products Application Note PDF 128 KB
AN-840 Jitter Specifications for Timing Signals Application Note PDF 442 KB
AN-838 Peak-to-Peak Jitter Calculations Application Note PDF 115 KB
AN-839 RMS Phase Jitter Application Note PDF 233 KB
AN-837 Overdriving the Crystal Interface Application Note PDF 133 KB
AN-832 Timing Budget and Accuracy Application Note PDF 131 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-830 Quartz Crystal Drive Level Application Note PDF 143 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-802 Crystal-Measuring Oscillator Negative Resistance Application Note PDF 136 KB
AN-801 Crystal-High Drive Level Application Note PDF 202 KB
AN-806 Power Supply Noise Rejection Application Note PDF 438 KB
AN-805 Recommended Ferrite Beads Application Note PDF 121 KB
PDN# : CQ-17-04(R1) Product Discontinuance Notice Product Discontinuation Notice PDF 606 KB
PDN# : CQ-17-04 Product Discontinuance Notice Product Discontinuation Notice PDF 599 KB
PCN# : A1602-01(R1) Add Greatek Taiwan as Alternate Assembly Product Change Notice PDF 611 KB
PCN# : A1602-01 Add Greatek Taiwan as Alternate Assembly Product Change Notice PDF 611 KB
PCN# : TB1504-01R1 Qty per Reel Standardization for Selective Packages Product Change Notice PDF 95 KB
PCN# : TB1504-01 Qty per Reel Standardization for Selective Packages Product Change Notice PDF 50 KB
PCN# : A1309-01 Changed of Traceability Mark Format Product Change Notice PDF 439 KB
Clock Distribution Overview 日本語 Overview PDF 217 KB
Timing Solutions Products Overview Overview PDF 4.11 MB
IDT Products for Radio Applications 日本語 Product Brief PDF 2.34 MB
IDT Clock Generation Overview 日本語 Overview PDF 1.83 MB