SLVSHF3 October   2024 LP5899-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Thermal Information
    4. 6.4 Recommended Operating Conditions
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 Timing Diagrams
    9. 6.9 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Internal Oscillator and Clocks
        1. 7.3.1.1 System Clock
        2. 7.3.1.2 Continuous Clock Serial Interface (CCSI) Clock
      2. 7.3.2 Continuous Clock Serial Interface (CCSI)
        1. 7.3.2.1 Command Format
        2. 7.3.2.2 Command Recognition and Synchronization
        3. 7.3.2.3 CCSI Command Queue
        4. 7.3.2.4 CCSI Start Bit and Check Bits Insertion and Removal
      3. 7.3.3 FIFO
        1. 7.3.3.1 FIFO level and Data Ready (DRDY) Interrupt
        2. 7.3.3.2 FIFO Clearance
      4. 7.3.4 Diagnostics
        1. 7.3.4.1  Undervoltage Lockout
        2. 7.3.4.2  Oscillator Fault Diagnostics
        3. 7.3.4.3  SPI Communications Loss
        4. 7.3.4.4  SPI Communications Error
          1. 7.3.4.4.1 Reset Timer
          2. 7.3.4.4.2 Chip Select (CS) Reset
          3. 7.3.4.4.3 CRC Error
          4. 7.3.4.4.4 Register write failure
        5. 7.3.4.5  CCSI Communications Loss
          1. 7.3.4.5.1 SIN Stuck-at Diagnostics
        6. 7.3.4.6  CCSI Communications Error
          1. 7.3.4.6.1 CHECK Bit Error
          2. 7.3.4.6.2 Data Integrity Diagnostics
          3. 7.3.4.6.3 CCSI Command Queue Overflow
        7. 7.3.4.7  FIFO Diagnostics
          1. 7.3.4.7.1 TXFIFO Overflow
          2. 7.3.4.7.2 TXFIFO Underflow
          3. 7.3.4.7.3 TXFIFO Single Error Detection (SED)
          4. 7.3.4.7.4 RXFIFO Overflow
          5. 7.3.4.7.5 RXFIFO Underflow
          6. 7.3.4.7.6 RXFIFO Single Error Detection (SED)
        8. 7.3.4.8  OTP CRC Error
        9. 7.3.4.9  Fault Masking
        10. 7.3.4.10 Diagnostics Table
    4. 7.4 Device Functional Modes
      1. 7.4.1 Unpowered
      2. 7.4.2 Initialization State
      3. 7.4.3 Normal State
      4. 7.4.4 Failsafe State
    5. 7.5 Programming
      1. 7.5.1 SPI Data Validity
      2. 7.5.2 Chip Select (CS) and SPI Reset Control
      3. 7.5.3 SPI Command Format
      4. 7.5.4 SPI Command Detail
    6. 7.6 Device Registers
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Programming Procedure
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Tape and Reel Information
    2. 11.2 Mechanical Data

Package Options

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

8.2.2 Detailed Design Procedure

At first the designer needs to determine the required CCSI data rate for the application. The minimum CCSI data rate is coming from the brightness information that needs to be transmitted to all the LED drivers within one frame period. The data sheet of the chosen LED driver gives more details about the minimum required CCSI data rate. In this application example the frame period is 33.33ms. There are 6 devices in the daisy chain (3 groups of 2 stackable mode) with 30 scan lines. When a data transmission efficiency of 70% is assumed (since there could be some idle time between transmitted CCSI commands), the minimum required CCSI data rate is 7.04Mbit/s. Therefore, the CCSI_DATA_RATE in register CCSICTRL is set to 8Mbit/s.

The SPI frequency is gerenally set to be in the similar range as the CCSI data rate. Therefore, in this application example the SPI frequency is set to 8MHz. The next step is to determine the TXFFLVL. TI recommends to set TXFFLVL larger than the maximum number of words that are forwarded for one CCSI command. The maximum number of words happen for a data write command with non-broadcast, e.g. write SRAM command. For this command, the number of words are equal to 3 times the number of cascaded devices plus one head byte. In this application example, the maximum number of words is 19 (3 x 6 + 1) words. Note that when SPI command FWD_WR_CRC is used, the TXFFLVL is ignored, and the forwarding only starts when the CRC word is correct. In addition, during the forwarding by the CCSI controller, the next SPI forward command can already be transmitted by the SPI controller because of the CCSI command queue in the LP5899-Q1.