SNAS573D January   2012  – September 2021 LMK01801

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison
    1. 5.1 Functional Configurations
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 Recommended Operating Conditions
    3. 7.3 Thermal Information
    4. 7.4 Electrical Characteristics
    5. 7.5 Serial MICROWIRE Timing Diagram
    6. 7.6 Typical Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 Differential Voltage Measurement Terminology
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1  High-Speed Clock Inputs (CLKin0/CLKin0* and CLKin1/CLKin1*)
      2. 9.3.2  Clock Distribution
      3. 9.3.3  Small Divider (1 to 8)
      4. 9.3.4  Large Divider (1 to 1045)
      5. 9.3.5  CLKout Analog Delay
      6. 9.3.6  CLKout0 to CLKout11 Digital Delay
      7. 9.3.7  CLKout12 and CLKout13 Digital Delay
      8. 9.3.8  Programmable Outputs
      9. 9.3.9  Clock Output Synchronization
      10. 9.3.10 Default Clock Outputs
    4. 9.4 Device Functional Modes
      1. 9.4.1 Programmable Mode
      2. 9.4.2 Pin Control Mode
      3. 9.4.3 Inputs / Outputs
        1. 9.4.3.1 CLKin0 and CLKin1
      4. 9.4.4 Input and Output Dividers
      5. 9.4.5 Fixed Digital Delay
        1. 9.4.5.1 Fixed Digital Delay - Example
      6. 9.4.6 Clock Output Synchronization (SYNC)
        1. 9.4.6.1 Dynamically Programming Digital Delay
          1. 9.4.6.1.1 Relative Dynamic Digital Delay
          2. 9.4.6.1.2 Relative Dynamic Digital Delay - Example
    5. 9.5 Programming
      1. 9.5.1 Recommended Programming Sequence
        1. 9.5.1.1 Overview
    6. 9.6 Register Map
      1. 9.6.1 Default Device Register Settings After Power On/Reset
      2. 9.6.2 Register R0
        1. 9.6.2.1 RESET
        2. 9.6.2.2 POWERDOWN
        3. 9.6.2.3 CLKoutX_Y_PD
          1. 9.6.2.3.1 CLKinX_BUF_TYPE
          2. 9.6.2.3.2 CLKinX_DIV
          3. 9.6.2.3.3 CLKinX_MUX
      3. 9.6.3 Register R1 and R2
        1. 9.6.3.1 CLKoutX_TYPE
      4. 9.6.4 Register R3
        1. 9.6.4.1 CLKout12_13_ADLY
        2. 9.6.4.2 CLKout12_13_HS, Digital Delay Half Shift
        3. 9.6.4.3 SYNC1_QUAL
        4. 9.6.4.4 SYNCX_POL_INV
        5. 9.6.4.5 NO_SYNC_CLKoutX_Y
        6. 9.6.4.6 CLKoutX_Y_OFFSET_PD
        7. 9.6.4.7 SYNCX_FAST
        8. 9.6.4.8 SYNCX_AUTO
      5. 9.6.5 Register R4
        1. 9.6.5.1 CLKout12_13_DDLY, Clock Channel Digital Delay
      6. 9.6.6 Register R5
        1. 9.6.6.1 CLKout12_ADLY_SEL[13], CLKout13_ADLY_SEL[14], Select Analog Delay
        2. 9.6.6.2 CLKoutX_Y_DIV Clock Output Divide
      7. 9.6.7 Register 15
        1. 9.6.7.1 uWireLock
  10. 10Application and Implementation
    1. 10.1 Typical Application
      1. 10.1.1 Detailed Design Procedure
        1. 10.1.1.1 Driving CLKin Inputs
          1. 10.1.1.1.1 Driving CLKin Pins With a Differential Source
          2. 10.1.1.1.2 Driving CLKin Pins With a Single-Ended Source
        2. 10.1.1.2 Termination and Use of Clock Output (Drivers)
          1. 10.1.1.2.1 Termination for DC-Coupled Differential Operation
          2. 10.1.1.2.2 Termination for AC-Coupled Differential Operation
          3. 10.1.1.2.3 Termination for Single-Ended Operation
  11. 11Power Supply Recommendations
    1. 11.1 Current Consumption
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 Pin Connection Recommendations
        1. 12.1.1.1 Vcc Pins and Decoupling
        2. 12.1.1.2 Unused clock outputs
        3. 12.1.1.3 Unused clock inputs
        4. 12.1.1.4 Unused GPIO (CLKoutTYPE_X)
        5. 12.1.1.5 Bias
        6. 12.1.1.6 In MICROWIRE Mode
    2. 12.2 Thermal Management
  13. 13Device and Documentation Support
    1. 13.1 Documentation Support
    2. 13.2 Receiving Notification of Documentation Updates
    3. 13.3 Support Resources
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

10.1.1.2 Termination and Use of Clock Output (Drivers)

When terminating clock drivers keep in mind these guidelines for optimum phase noise and jitter performance:

  • Transmission line theory should be followed for good impedance matching to prevent reflections.
  • Clock drivers should be presented with the proper loads. For example:
    • LVDS drivers are current drivers and require a closed current loop.
    • LVPECL drivers are open emitters and require a DC path to ground.
  • Receivers should be presented with a signal biased to their specified DC bias level (common mode voltage) for proper operation. Some receivers have self-biasing inputs that automatically bias to the proper voltage level. In this case, the signal should normally be AC coupled.

It is possible to drive a non-LVPECL or non-LVDS receiver with an LVDS or LVPECL driver as long as the above guidelines are followed. Check the datasheet of the receiver or input being driven to determine the best termination and coupling method to be sure that the receiver is biased at its optimum DC voltage (common mode voltage).

For example, when driving the OSCin/OSCin* input of the LMK04800 family, OSCin/OSCin* should be AC coupled because OSCin/ OSCin* biases the signal to the proper DC level. This is only slightly different from the AC coupled cases described in Section 10.1.1.1.2 because the DC blocking capacitors are placed between the termination and the OSCin/OSCin* pins, but the concept remains the same. The receiver (OSCin/OSCin*) sets the input to the optimum DC bias voltage (common mode voltage), not the driver.