SNLA267A March   2019  – June 2019 DS90UB953-Q1 , DS90UB954-Q1 , DS90UB960-Q1

 

  1.   How to Design a FPD-Link III System Using DS90UB953-Q1 and DS90UB954-Q1
    1.     Trademarks
    2. 1 Overview
      1. 1.1 System Level Functionality
    3. 2 Basic Design Rules
      1. 2.1 IDX and MODE Pin Verification
        1. 2.1.1 REF Clock, CLK IN, AON and Frequency Selection
          1. 2.1.1.1 Synchronous Mode
          2. 2.1.1.2 Non-Synchronous CLK_IN Mode
          3. 2.1.1.3 Non-Synchronous AON Mode
          4. 2.1.1.4 CSI Throughput
          5. 2.1.1.5 Clocking and Frequency Selection Example
      2. 2.2 Successful I2C Communication With 953 and 954
        1. 2.2.1 Aliasing
        2. 2.2.2 Port Selection on 954
      3. 2.3 I2C Passthrough Verification
      4. 2.4 Basic Diagnostic and Error Registers
    4. 3 Designing the Link Between SER and DES
      1. 3.1 Back Channel Configuration
      2. 3.2 BIST
        1. 3.2.1 BIST Configuration and Status
        2. 3.2.2 BIST Procedure
        3. 3.2.3 List of Registers Used in BIST Script
      3. 3.3 AEQ
      4. 3.4 CML Out
    5. 4 Designing Link Between SER and Image Sensor
      1. 4.1 Sensor Initialization Using SER GPIOs
      2. 4.2 CLKOUT
    6. 5 Designing Link Between DES and ISP
      1. 5.1 Frame Sync
        1. 5.1.1 Using SER GPIOs From the DES
        2. 5.1.2 Internal and External Frame Sync Configuration
        3. 5.1.3 Tables for Using GPIOs and Frame Sync
      2. 5.2 Port Forwarding
      3. 5.3 Pattern Generation
        1. 5.3.1 Accessing Indirect Registers
        2. 5.3.2 Pattern Generation From DES to ISP and SER to DES
    7. 6 Hardware Design
      1. 6.1 Basic I2C Connectors
        1. 6.1.1 I2C Pullups for SDA and SCL
      2. 6.2 AC Capacitor on FPD3 Link
      3. 6.3 Capacitance Used in Loop Filter
      4. 6.4 Critical Signal Routing
      5. 6.5 Time Domain Reflection
      6. 6.6 Return Loss and Insertion Loss
      7. 6.7 Power-over-Coax (PoC)
      8. 6.8 Voltage and Temperature Sensing
    8. 7 Appendix
      1. 7.1 Scripts
        1. 7.1.1  BIST Script
        2. 7.1.2  Example Sensor Initialization Script
        3. 7.1.3  CSI Enable and Port Forwarding Script
        4. 7.1.4  Enabling CMLOUT FPD3 RX Port 0 on 954
        5. 7.1.5  Remote Enabled SER GPIO Toggle Script
        6. 7.1.6  Local SER GPIO Toggle Script
        7. 7.1.7  Internal FrameSync on 953 GPIO1
        8. 7.1.8  External FrameSync on 953 GPIO0
        9. 7.1.9  SER GPIOs as Inputs and Output to DES GPIO
        10. 7.1.10 Pattern Generation on the 953 Script
        11. 7.1.11 Pattern Generation on the 954 Script
        12. 7.1.12 Monitor Errors for Predetermined Time Script
        13. 7.1.13 954 and 953 CSI Register Check Script
        14. 7.1.14 Time Till Lock Script on 953
      2. 7.2 Acknowledgments
  2.   Revision History

6.7 Power-over-Coax (PoC)

The Power-over-Coax (PoC) capability requires the use of circuitry following certain specifications connected to both ends of the cable. These specifications include impedance versus frequency characteristics and return loss. The PoC circuit must have low impedance at DC, but to not interfere with the data path, the characteristic impedance must be large over the band of the forward channel and back channel (10 MHz to 2 GHz) compared to the 50-Ω impedance of the coax line.

The critical consideration is the return loss profile after adding the PoC network. Limits on return loss make sure that the impedance of the PoC network is high enough that high-speed path signal integrity is maintained. The PoC network offers low impedance at DC to allow an efficient power transfer to the DC-DC powering the serializer and the camera, but also offers high impedance at the frequencies used for data transfer. Depending upon the current consumption of the camera and serializer board, there could be 200 to 500 mA of current going through the network. As a result, the engineer must check the inductor current limits before finalizing components to ensure that the PoC network components do not saturate at these current levels. A good starting point for the PoC Network to provide high impedance at the high frequencies is to use the recommended network in the EVM schematic.

For more information, see the Power-over-Coax design guidelines for the DS90UB953-Q1 application note (SNLA272).