SBOS571C August   2011  – August 2018 BUF20800-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Block Diagram
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 General-call Reset and Power-up
      2. 7.3.2 Output Voltage
      3. 7.3.3 Output Latch
      4. 7.3.4 Programmable VCOM
      5. 7.3.5 REFH and REFL Input range
    4. 7.4 Device Functional Modes
      1. 7.4.1 Replacement of Traditional Gamma Buffer
      2. 7.4.2 Dynamic Gamma Control
    5. 7.5 Programming
      1. 7.5.1 Two-wire Bus Overview
      2. 7.5.2 Data Rates
      3. 7.5.3 Read/Write Operations
        1. 7.5.3.1 Writing
        2. 7.5.3.2 Reading
      4. 7.5.4 Register Maps
        1. 7.5.4.1 Addressing the BUF20800-Q1
      5. 7.5.5 Registers
  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
        1. 8.2.2.1 Input Capacitor Selection
        2. 8.2.2.2 REFH and REFL Voltage Settings
      3. 8.2.3 Application Curves
      4. 8.2.4 Configuration for 20 Gamma Channels
      5. 8.2.5 Configuration for 22 Gamma Channels
      6. 8.2.6 The BUF20800-Q1 in Industrial Applications
      7. 8.2.7 Total TI Panel Solution
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 General PowerPAD Design Considerations
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.1 Overview

The BUF20800-Q1 programmable voltage reference allows fast, easy adjustment of 18 programmable reference outputs and two channels for VCOM adjustment, each with 10-bit resolution. It offers very simple, time-efficient adjustment of the gamma reference and VCOM voltages. The BUF20800-Q1 is programmed through a high-speed, standard, two-wire interface. The BUF20800-Q1 features a double-register structure for each DAC channel to simplify the implementation of dynamic gamma control. This structure allows pre-loading of register data and rapid updating of all channels simultaneously.

Buffers 1−9 are able to swing to within 200mV of the positive supply rail, and to within 0.6V of the negative supply rail. Buffers 10−18 are able to swing to within 0.8V of the positive supply rail and to within 200mV of the negative supply rail.

The BUF20800-Q1 can be powered using an analog supply voltage from 7V to 18V, and a digital supply from 2V to 5.5V. The digital supply must be applied prior to or simultaneously with the analog supply to avoid excessive current and power consumption; damage to the device may occur if it is left connected only to the analog supply for extended periods of time. Figure 7 shows the power supply timing requirements.

BUF20800-Q1 appinfo_pwrtimreqs_bos571.gifFigure 7. Power Supply Timing Requirements

Figure 14 shows the BUF20800-Q1 in a typical configuration. In this configuration, the BUF20800-Q1 device address is 74h. The output of each digital-to-analog converter (DAC) is immediately updated as soon as data are received in the corresponding register (LD = 0).

For maximum dynamic range, set VREFH = VS − 0.2 V and VREFL = GND + 0.2 V.