SLLS980E June   2009  – November 2016 SN75LVDS83A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Dissipation Ratings
    7. 7.7 Timing Requirements
    8. 7.8 Switching Characteristics
    9. 7.9 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 TTL Input Data
      2. 9.3.2 LVDS Output Data
    4. 9.4 Device Functional Modes
      1. 9.4.1 Input Clock Edge
      2. 9.4.2 Low Power Mode
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Signal Connectivity
      2. 10.1.2 PCB Routing
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Power Up Sequence
      3. 10.2.3 Application Curve
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 Board Stackup
      2. 12.1.2 Power and Ground Planes
      3. 12.1.3 Traces, Vias, and Other PCB Components
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Receiving Notification of Documentation Updates
    2. 13.2 Community Resources
    3. 13.3 Trademarks
    4. 13.4 Electrostatic Discharge Caution
    5. 13.5 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

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9 Detailed Description

9.1 Overview

The Flatlink™ is a LVDS SerDes data transmission system. The SN75LVDS83A device takes in three (or four) data words each containing seven single-ended data bits and converts this to an LVDS serial output. Each serial output runs at seven times that of the parallel data rate. The deserializer (receiver) device operates in the reverse manner. The three (or four) LVDS serial inputs are transformed back to the original seven-bit parallel single-ended data. Flatlink™ devices are available in 21:3 or 28:4 SerDes ratios.

The 21-bit devices are designed for 6-bit RGB video for a total of 18 bits in addition to three extra bits for horizontal synchronization, vertical synchronization, and data enable. The 28-bit devices are intended for 8-bit RGB video applications. Again, the extra four bits are for horizontal synchronization, vertical synchronization, data enable, and the remaining is the reserved bit. These 28-bit devices can also be used in 6-bit and 4-bit RGB applications as shown in the subsequent system diagrams.

9.2 Functional Block Diagram

SN75LVDS83A fbd_lls846.gif

9.3 Feature Description

9.3.1 TTL Input Data

The data inputs to the transmitter come from the graphics processor and consist of up to 24 bits of video information, a horizontal synchronization bit, a vertical synchronization bit, an enable bit, and a spare bit.

The data can be loaded into the registers upon either the rising or falling edge of the input clock selectable by the CLKSEL pin. Data inputs are 1.8 V to 3.3 V tolerant for the SN75LVDS83A and can connect directly to low-power, low-voltage application and graphic processors. The bit mapping is listed in Table 1.

Table 1. Pixel Bit Ordering

RED GREEN BLUE
LSB R0 G0 B0
R1 G1 B1
R2 G2 B2
4-bit MSB R3 G3 B3
R4 G4 B4
6-bit MSB R5 G5 B5
R6 G6 B6
8-bit MSB R7 G7 B7

9.3.2 LVDS Output Data

The pixel data assignment is listed in Table 2 for 24-bit, 18-bit, and 12-bit color hosts.

Table 2. Pixel Data Assignment

SERIAL CHANNEL DATA BITS 8-BIT 6-BIT 4-BIT
FORMAT-1(1) FORMAT-2(2) FORMAT-3(3) NON-LINEAR STEP SIZE(4) LINEAR STEP SIZE(5)
Y0 D0 R0 R2 R2 R0 R2 VCC
D1 R1 R3 R3 R1 R3 GND
D2 R2 R4 R4 R2 R0 R0
D3 R3 R5 R5 R3 R1 R1
D4 R4 R6 R6 R4 R2 R2
D6 R5 R7 R7 R5 R3 R3
D7 G0 G2 G2 G0 G2 VCC
Y1 D8 G1 G3 G3 G1 G3 GND
D9 G2 G4 G4 G2 G0 G0
D12 G3 G5 G5 G3 G1 G1
D13 G4 G6 G6 G4 G2 G2
D14 G5 G7 G7 G5 G3 G3
D15 B0 B2 B2 B0 B2 VCC
D18 B1 B3 B3 B1 B3 GND
Y2 D19 B2 B4 B4 B2 B0 B0
D20 B3 B5 B5 B3 B1 B1
D21 B4 B6 B6 B4 B2 B2
D22 B5 B7 B7 B5 B3 B3
D24 HSYNC HSYNC HSYNC HSYNC HSYNC HSYNC
D25 VSYNC VSYNC VSYNC VSYNC VSYNC VSYNC
D26 ENABLE ENABLE ENABLE ENABLE ENABLE ENABLE
Y3 D27 R6 R0 GND GND GND GND
D5 R7 R1 GND GND GND GND
D10 G6 G0 GND GND GND GND
D11 G7 G1 GND GND GND GND
D16 B6 B0 GND GND GND GND
D17 B7 B1 GND GND GND GND
D23 RSVD RSVD GND GND GND GND
CLKOUT CLKIN CLK CLK CLK CLK CLK CLK
(1) 2 MSBs of each color transmitted over 4th serial data channel (Y3). Dominant data format for LCD panel.
(2) 2 LSBs of each color transmitted over 4th serial data channel. System designer needs to verify the data format by checking with the LCD display data sheet.
(3) 24-bit color host to 18-bit color LCD panel display application.
(4) Increased dynamic range of the entire color space at the expense of non-linear step sizes between each step.
(5) Linear step size with less dynamic range.

9.4 Device Functional Modes

9.4.1 Input Clock Edge

The transmission of data bits D0 through D27 occurs as each are loaded into registers upon the edge of the CLKIN signal, where the rising or falling edge of the clock may be selected through CLKSEL. The selection of a clock rising edge occurs by inputting a high level to CLKSEL, which is achieved by populating pullup resistor to pull CLKSEL is high. Inputting a low level to select a clock falling edge is achieved by directly connecting CLKSEL to GND.

9.4.2 Low Power Mode

The SN75LVDS83A can be put in low-power consumption mode by active-low input SHTDN#.

Connecting terminal SHTDN to GND inhibits the clock and shut off the LVDS output drivers for lower power consumption. A low level on this signal clears all internal registers to a low level.

Populate a pullup to VCC on SHTDN# to enable the device for normal operation.

SN75LVDS83A sch_diag_lls980.gif Figure 13. Equivalent Input and Output Schematic Diagrams