SNLS407D April   2012  – October 2014 DS90UB925Q-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 Handling Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 DC Electrical Characteristics
    6. 6.6 AC Electrical Characteristics
    7. 6.7 Recommended Timing for the Serial Control Bus
    8. 6.8 Switching Characteristics
    9. 6.9 Typical Charateristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  High Speed Forward Channel Data Transfer
      2. 7.3.2  Low Speed Back Channel Data Transfer
      3. 7.3.3  Backward Compatible Mode
      4. 7.3.4  Common Mode Filter Pin (CMF)
      5. 7.3.5  Video Control Signal Filter
      6. 7.3.6  EMI Reduction Features
        1. 7.3.6.1 Input SSC Tolerance (SSCT)
      7. 7.3.7  LVCMOS VDDIO Option
      8. 7.3.8  Power Down (PDB)
      9. 7.3.9  Remote Auto Power Down Mode
      10. 7.3.10 Input PCLK Loss Detect
      11. 7.3.11 Serial Link Fault Detect
      12. 7.3.12 Pixel Clock Edge Select (RFB)
      13. 7.3.13 Low Frequency Optimization (LFMODE)
      14. 7.3.14 Interrupt Pin — Functional Description And Usage (INTB)
      15. 7.3.15 Internal Pattern Generation
      16. 7.3.16 GPIO[3:0] and GPO_REG[8:4]
        1. 7.3.16.1 GPIO[3:0] Enable Sequence
        2. 7.3.16.2 GPO_REG[8:4] Enable Sequence
      17. 7.3.17 I2S Transmitting
        1. 7.3.17.1 Secondary I2S Channel
      18. 7.3.18 Built In Self Test (BIST)
        1. 7.3.18.1 BIST Configuration and Status
          1. 7.3.18.1.1 Sample BIST Sequence
        2. 7.3.18.2 Forward Channel And Back Channel Error Checking
    4. 7.4 Device Functional Modes
      1. 7.4.1 Configuration Select (MODE_SEL)
      2. 7.4.2 Repeater Application
        1. 7.4.2.1 Repeater Configuration
        2. 7.4.2.2 Repeater Connections
    5. 7.5 Programming
    6. 7.6 Register Maps
  8. 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
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
    1. 9.1 Power Up Requirements and PDB Pin
    2. 9.2 CML Interconnect Guidelines
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

8.1 Application Information

The DS90UB925Q-Q1, in conjunction with the DS90UB926Q-Q1, is intended for interface between a host (graphics processor) and a Display. It supports a 24-bit color depth (RGB888) and high definition (720p) digital video format. It can receive a three 8-bit RGB stream with a pixel rate up to 85 MHz together with three control bits (VS, HS and DE) and three I2S-bus audio stream with an audio sampling rate up to 192 kHz.

8.2 Typical Application

30143344.gifFigure 23. Typical Connection Diagram
30143327.gifFigure 24. Typical Display System Diagram
30143326.gifFigure 25. Typical Camera Applications Diagram

8.2.1 Design Requirements

For the typical design application, use the following as input parameters.

Table 7. Design Parameters

DESIGN PARAMETER EXAMPLE VALUE
VDDIO 1.8 V or 3.3 V
VDD33 3.3 V
AC Coupling Capacitor for DOUT± 100 nF
PCLK Frequency 85 MHz

8.2.2 Detailed Design Procedure

Figure 23 shows a typical application of the DS90UB925Q-Q1 serializer for an 85 MHz 24-bit Color Display Application. The camera application has the same recommended connections. The CML outputs must have an external 0.1 μF AC coupling capacitor on the high speed serial lines. The serializer has an internal termination. Bypass capacitors are placed near the power supply pins. At a minimum, six (6) 4.7μF capacitors and two (2) additional 1μF capacitors should be used for local device bypassing. Ferrite beads are placed on the two (2) VDDs (VDD33 and VDDIO) for effective noise suppression. The interface to the graphics source is with 3.3V LVCMOS levels, thus the VDDIO pin is connected to the 3.3 V rail. A RC delay is placed on the PDB signal to delay the enabling of the device until power is stable.

8.2.3 Application Curves

926_78m_processed.gifFigure 26. Serializer Eye Diagram with 78 MHz TX Pixel Clock
140611_091342_processed.gifFigure 27. Serializer CML Output with 78 MHz TX Pixel Clock