The 840NT4-01I is clock generator designed to provide ethernet and USB clocks for Freescale B4/ T4-based systems. The 840NT4-01I utilizes Renesas' FemtoClock NG® PLL technology to synthesize eight low phase-jitter Ethernet reference clocks. The clock generator also provides a 24MHz USB reference clock and a 25MHz reference output.


  • Ten LVCMOS clock outputs:
    • Five LVCMOS 125MHz Ethernet outputs
    • Three LVCMOS 25MHz /125MHz Ethernet outputs
    • One LVCMOS 24MHz USB output
    • One LVCMOS 25MHz REF output
  • QREF output; can be used to drive X1 of other devices, saving a crystal
  • Selectable crystal input, or differential LVPECL input; test mode
  • RMS Phase Jitter, 125MHz, integration range 12kHz – 20MHz: 0.75ps (typical)
  • Cycle-to-Cycle jitter: 75ps (typical)
  • Flexible voltage supply modes; supports legacy and future system requirements, minimizes power consumption
  • Core voltage: (VDD, VDD_XTAL, VDDA) / 
    Output voltage: (VDDO_A, VDDO_B, VDDO_C, VDDO_REF)
    Core / Output
    3.3V / 3.3V
    3.3V / 2.5V
    3.3V / 1.8V
    2.5V / 2.5V
    2.5V / 1.8V
  • -40°C to +85°C ambient operating temperature
  • Space-saving Pb-free, 48-pin 7 × 7 mm QFN; minimal board space
  • Lead-free (RoHS 6) packaging

Product Options

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

Documentation & Downloads

Title Other Languages Type Format File Size Date
Datasheets & Errata
840NT4-01 Datasheet Datasheet PDF 760 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-845 Termination - LVCMOS Application Note PDF 146 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-833 Differential Input Self Oscillation Prevention Application Note PDF 180 KB
AN-834 Hot-Swap Recommendations Application Note PDF 153 KB
AN-837 Overdriving the Crystal Interface Application Note PDF 133 KB
AN-832 Timing Budget and Accuracy Application Note PDF 131 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
PCN# : A1904-01 Add Greatek, Taiwan as an Alternate Assembly Facility Product Change Notice PDF 983 KB
PCN# : W1308-01 Change of Passivation Thickness Product Change Notice PDF 941 KB
840NT4-01i IBIS Model Model - IBIS ZIP 110 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