SPRACL9 May   2019 66AK2E05 , 66AK2H06 , 66AK2H12 , 66AK2H14 , AM5K2E02 , AM5K2E04 , TMS320C6652 , TMS320C6654 , TMS320C6655 , TMS320C6657 , TMS320C6670 , TMS320C6671 , TMS320C6672 , TMS320C6674 , TMS320C6678

 

  1.   KeyStone Multicore Device Family Schematic Checklist
    1.     Trademarks
    2. 1 Introduction
    3. 2 Hardware Design Guide
    4. 3 Device Comparison
      1. 3.1 KeyStone II Devices
      2. 3.2 KeyStone I Devices
    5. 4 Power Management Solutions
    6. 5 Recommendations Specific to all KeyStone Devices
      1. 5.1 EVM vs Data Sheet
      2. 5.2 Critical Connections
        1. 5.2.1 Power
        2. 5.2.2 Clocking
        3. 5.2.3 LJCB Differential Clock Inputs
        4. 5.2.4 Clock Termination
        5. 5.2.5 Unused Clock Inputs
        6. 5.2.6 Reset
        7. 5.2.7 GPIO/Boot Configuration
        8. 5.2.8 JTAG and EMU
    7. 6 Peripherals
      1. 6.1 DDR3 Interface
        1. 6.1.1  EMIF16
        2. 6.1.2  SerDes
        3. 6.1.3  HyperLink
        4. 6.1.4  PCIe
        5. 6.1.5  SRIO
        6. 6.1.6  SGMII
        7. 6.1.7  MDIO
        8. 6.1.8  TSIP
        9. 6.1.9  I2C
        10. 6.1.10 SPI
        11. 6.1.11 UART
        12. 6.1.12 I/O Buffers and Termination
    8. 7 Recommendations Specific to KeyStone II Devices
      1. 7.1 Peripherals
        1. 7.1.1 USB
    9. 8 General Recommendations
      1. 8.1 Before You Begin
        1. 8.1.1 Documentation
        2. 8.1.2 Pinout
    10. 9 References

5.2.3 LJCB Differential Clock Inputs

  • Many reference clock inputs are connected to a low-jitter clock buffers (LJCB) in the KeyStone devices. This buffer is designed to interface with LVDS, LVPECL, and HCSL clock input levels using AC coupling capacitors.
  • The LJCB has internal termination and an internal common mode voltage generator so no external termination is needed between the AC coupling capacitors and the KeyStone device.
  • The driver selected for your design may require termination on the output. You should review the device-specific data manual for the driver to determine what termination is necessary.
spracl9-ljcb-differential-clock-inputs.gifFigure 1. LJCB Differential Clock Inputs