SNAU296 December   2023 LMK5C33414A

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2EVM Quick Start
  6. 3EVM Configuration
    1. 3.1  Power Supply
    2. 3.2  Logic Inputs and Outputs
    3. 3.3  Switching Between I2C and SPI
    4. 3.4  Generating SYSREF Request
    5. 3.5  XO Input
      1. 3.5.1 48-MHz TCXO (Default)
      2. 3.5.2 External Clock Input
      3. 3.5.3 Additional XO Input Options
      4. 3.5.4 APLL Reference Options
    6. 3.6  Reference Clock Inputs
    7. 3.7  Clock Outputs
    8. 3.8  Status Outputs and LEDs
    9. 3.9  Requirements for Making Measurements
    10. 3.10 Typical Phase Noise Characteristics
  7. 4EVM Schematics
    1. 4.1  Power Supply Schematic
    2. 4.2  Alternative Power Supply Schematic
    3. 4.3  Power Distribution Schematic
    4. 4.4  LMK5C33414A and Input References IN0 to IN3 Schematic
    5. 4.5  Clock Outputs OUT0 to OUT3 Schematic
    6. 4.6  Clock Outputs OUT4 to OUT9 Schematic
    7. 4.7  Clock Outputs OUT10 to OUT13 and Clock Inputs IN2 and IN3 Schematic
    8. 4.8  XO Schematic
    9. 4.9  Logic I/O Interfaces Schematic
    10. 4.10 USB2ANY Schematic
  8. 5EVM Bill of Materials
    1. 5.1 Loop Filter and Vibration Nonsensitive Capacitors
  9. 6Appendix A - TICS Pro LMK5C33414A Software
    1. 6.1  Using the Start Page
      1. 6.1.1 Step 1
      2. 6.1.2 Step 2
      3. 6.1.3 Step 3
      4. 6.1.4 Step 4
      5. 6.1.5 Step 5
      6. 6.1.6 Step 6
      7. 6.1.7 Step 7
    2. 6.2  Using the Status Page
    3. 6.3  Using the Input Page
      1. 6.3.1 Cascaded Configurations
        1. 6.3.1.1 Cascade VCO to APLL Reference
    4. 6.4  Using APLL1, APLL2, and APLL3 Pages
      1. 6.4.1 APLL DCO
    5. 6.5  Using the DPLL1, DPLL2, and DPLL3 Pages
    6. 6.6  Using the Validation Page
      1. 6.6.1 DPLL DCO
    7. 6.7  Using the GPIO Page
    8. 6.8  SYNC/SYSREF/1-PPS Page
    9. 6.9  Using the Outputs Page
    10. 6.10 EEPROM Page
    11. 6.11 Design Report Page

3.5.2 External Clock Input

Another option is to feed an external clock to the XO SMA port (J8) to drive the XO input. See Figure 3-9. This path can be connected to the XO input pins. Y1 needs to be powered down when using the external XO input path. To power down Y1 and use an external XO input, the jumper on JP4 must be removed. Suggested XO frequencies for best device performance are frequencies of 38.88 MHz and 48 MHz. When using an external XO input, TI recommends to remove the capacitor (C71) connecting the TCXO output to the XO input of the LMK5C33414A. This prevents any risk of backdriving the onboard TCXO.