The 8T49N028 is a low RMS phase jitter Clock Synthesizer with selectable internal crystal oscillator or external clock references and eight outputs, configurable as either LVDS, LVPECL or High Impedance.
 
After power up, two frequency select pins determine one of up to four different sets of factory preprogrammed crystal or input frequency and output frequency configurations. From a single input reference, as many as three different output frequencies may be selected for the output banks: two of these frequencies can be generated by the internal crystal oscillator, and/or external clock pre-divider, and/or A output divider, and/or B output divider. The third output frequency is from the B output divider. Device pre-programming can be overwritten through the provided I2C interface.
 
Examples of valid frequency configuration setups illustrate this device's flexibility, and are shown in Table 3A. The specific internal register settings for each of the four frequency sets are specified by an IDT order code. Custom codes can be provided by contacting IDT.

Features

  • Fourth Generation FemtoClock NG PLL technology
  • Eight selectable LVPECL or LVDS outputs (bank selectable, two output channels per bank)
  • CLK, nCLK input pair can accept the following differential input levels: LVPECL, LVDS, HCSL
  • FemtoClock NG VCO Range: 1.92GHz - 2.5GHz
  • Bank A and B output frequencies are mux selectable from internal crystal oscillator, reference clock input, output divider A or output divider B
  • Clock from OUTPUT DIVIDER A, RMS phase jitter at 156.25MHz
    (12KHz - 20MHz): 225fs (typical)
  • Clock from OUTPUT DIVIDER B, RMS phase jitter at 156.25MHz
    (12KHz - 20MHz): 219fs (typical)
  • Clock from OUTPUT DIVIDER B, RMS phase jitter at 156.25MHz
    (10kHz - 1MHz): 165fs (typical) Full 2.5V or 3.3V power supply
  • Full 2.5V or 3.3V power supply
  • I2C programming interface
  • PCI Express (2.5 Gb/S), Gen 2 (5 Gb/s) and Gen 3 (8 Gb/s) jitter compliant
  • -40°C to 85°C ambient operating temperature
  • 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
Availability
Active 48 I Yes Reel
Availability

Documentation & Downloads

Title Other Languages Type Format File Size Date
Datasheets & Errata
8T49N028 Datasheet Datasheet PDF 1.62 MB
User Guides & Manuals
Programmable FemtoClock Ordering Product Information Manual PDF 140 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-846 Termination - LVDS Application Note PDF 133 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-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-833 Differential Input Self Oscillation Prevention Application Note PDF 180 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
PCNs & PDNs
PCN# : A1904-01 Add Greatek, Taiwan as an Alternate Assembly Facility Product Change Notice PDF 983 KB
PCN# : A1611-02 Add JCET China as Alternate Assembly and Change of Material Set at Alternate Assembly Location Product Change Notice PDF 583 KB
PCN# : W1308-01 Change of Passivation Thickness Product Change Notice PDF 941 KB
Other
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