SNAS579G March   2012  – December 2014 LMK00105

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Functional Block Diagram
  4. 4 Revision History
  5. 5 Pin Configuration and Diagrams
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Vdd and Vddo Power Supplies
      2. 7.3.2 Clock Input
        1. 7.3.2.1 Selection of Clock Input
          1. 7.3.2.1.1 CLKin/CLKin* Pins
          2. 7.3.2.1.2 OSCin/OSCout Pins
      3. 7.3.3 Clock Outputs
        1. 7.3.3.1 Output Enable Pin
        2. 7.3.3.2 Using Less than Five Outputs
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Clock Inputs
      2. 8.1.2 Clock Outputs
    2. 8.2 Typical Applications
      1. 8.2.1 Typical Application Block Diagram
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Crystal Interface
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
  9. 9 Power Supply Recommendations
    1. 9.1 Power Supply Filtering
    2. 9.2 Power Supply Ripple Rejection
    3. 9.3 Power Supply Bypassing
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Ground Planes
      2. 10.1.2 Power Supply Pins
      3. 10.1.3 Differential Input Termination
      4. 10.1.4 Output Termination
    2. 10.2 Layout Example
    3. 10.3 Thermal Management
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Differential Voltage Measurement Terminology
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RTW|24
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.2 Power Supply Ripple Rejection

In practical system applications, power supply noise (ripple) can be generated from switching power supplies, digital ASICs or FPGAs, etc. While power supply bypassing will help filter out some of this noise, it is important to understand the effect of power supply ripple on the device performance. When a single-tone sinusoidal signal is applied to the power supply of a clock distribution device, such as LMK00105, it can produce narrow-band phase modulation as well as amplitude modulation on the clock output (carrier). In the singleside band phase noise spectrum, the ripple-induced phase modulation appears as a phase spur level relative to the carrier (measured in dBc).

For the LMK00105, power supply ripple rejection (PSRR), was measured as the single-sideband phase spur level (in dBc) modulated onto the clock output when a ripple signal was injected onto the Vddo supply. The PSRR test setup is shown in Figure 22.

LMK00105 30180740.gifFigure 22. PSRR Test Setup

A signal generator was used to inject a sinusoidal signal onto the Vddo supply of the DUT board, and the peak-to-peak ripple amplitude was measured at the Vddo pins of the device. A limiting amplifier was used to remove amplitude modulation on the differential output clock and convert it to a single-ended signal for the phase noise analyzer. The phase spur level measurements were taken for clock frequencies of 100 MHz under the following power supply ripple conditions:

  • Ripple amplitude: 100 mVpp on Vddo = 2.5 V
  • Ripple frequency: 100 kHz

Assuming no amplitude modulation effects and small index modulation, the peak-to-peak deterministic jitter (DJ) can be calculated using the measured single-sideband phase spur level (PSRR) as follows:

Equation 5. DJ (ps pk-pk) = [(2 * 10(PSRR/20)) / (π * fclk)] * 1012