LTC6909 - 1 to 8 Output, Multiphase Silicon Oscillator with Spread Spectrum Modulation

The LTC6909 is an easy to use precision oscillator that can provide 1-, 2-, 3-, 4-, 5-, 6-, 7- or 8-phase synchronized outputs. The LTC6909 also offers spread spectrum frequency modulation (SSFM), which can be enabled to improve electromagnetic compatibility (EMC) performance.

Eight separate outputs provide up to eight rail-to-rail, 50% duty cycle clock signals. Using three logic inputs, the outputs are configured for phase separation, ranging from 45° to 120° (three to eight phases). The clock outputs can also be held low or configured for Hi-Z. A single resistor, combined with the phase configuration, sets the output frequency, based on the following formula:

The LTC6909 can be used in applications requiring only one or two output phases. Alternatively, the LTC6908 family of parts provides the same two output signals but in a smaller SOT-23 or 2mm × 3mm DFN package. The LTC6908-1 provides complimentary (180°) outputs while the LTC6908-2 provides quadrature (90°) outputs.

  • 1-, 2-, 3-, 4-, 5-, 6-, 7- or 8-Phase Outputs
  • One External Resistor Sets the Output Frequency from 12.5kHz to 6.67MHz
  • Optional Spread Spectrum Frequency for Improved EMI Performance
  • ±10% Frequency Spreading
  • Outputs Can Be Held Low or Floated (Hi-Z)
  • Three Spread Spectrum Modulation Rates fOUT/16, fOUT/32 and fOUT/64
  • 400μA Supply Current
  • Operates from a Single 2.7V to 5.5V Supply
  • Fast Start-Up Time
  • First Cycle Accurate
  • Outputs Are High Impedance Until Frequency Settles
  • MS16 Package
Typical Application
LTC6909 Typical Application
LTC6909 Typical Application
  • Synchronizing Multiple Switching Power Supplies
LTC6909 Package Drawing
Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
Demo Boards
Part NumberDescriptionPrice
DC1446ALTC6909 DEMO BOARD$75.00
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