SNLS544B September   2016  – October 2019 DS280BR820

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Simplified Schematic
  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 Electrical Characteristics – Serial Management Bus Interface
    7. 6.7 Timing Requirements – Serial Management Bus Interface
    8. 6.8 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 Device Data Path Operation
      2. 7.3.2 AC-Coupled Receiver Inputs
      3. 7.3.3 Signal Detect
      4. 7.3.4 2-Stage CTLE
      5. 7.3.5 Driver DC Gain Control
      6. 7.3.6 FIR Filter (Limiting Mode)
      7. 7.3.7 Configurable SMBus Address
    4. 7.4 Device Functional Modes
      1. 7.4.1 SMBus Slave Mode Configuration
      2. 7.4.2 SMBus Master Mode Configuration (EEPROM Self Load)
    5. 7.5 Programming
      1. 7.5.1 Transfer of Data with the SMBus Interface
    6. 7.6 Register Maps
      1. 7.6.1 Register Types: Global, Shared, and Channel
      2. 7.6.2 Global Registers: Channel Selection and ID Information
        1. Table 2. Global Register Map
      3. 7.6.3 Shared Registers
        1. Table 3. Shared Register Map
      4. 7.6.4 Channel Registers
        1. Table 4. Channel Register Map
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Backplane and Mid-Plane Reach Extension
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
      2. 8.2.2 Front-Port Applications
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
        1. 8.2.3.1 Pattern Generator Characteristics
        2. 8.2.3.2 Equalizing Moderate Pre-Channel Loss
        3. 8.2.3.3 Equalizing High Pre-Channel Loss
        4. 8.2.3.4 Equalizing High Pre-Channel Loss and Moderate Post-Channel Loss
        5. 8.2.3.5 Output in FIR Limiting Mode with 16T Pattern
    3. 8.3 Initialization Set Up
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
      1. 10.2.1 Stripline Example
      2. 10.2.2 Microstrip 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 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary

Package Options

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

7.3.4 2-Stage CTLE

The continuous-time linear equalizer (CTLE) in the DS280BR820 consists of two stages which are configurable via the SMBus channel registers. This CTLE is designed to be highly linear to allow the DS280BR820 to preserve the transmitter's pre-cursor and post cursor signal characteristics. This highly linear behavior enables the DS280BR820 to be used in applications that use protocols such as link training, where it is important to recover and pass through incremental changes in transmit equalization.

Each stage in the CTLE has 3-bit boost control. The first CTLE stage provides a coarse adjustment of the total boost. Larger settings correspond to higher total boost. The first stage can be bypassed entirely to achieve the lowest possible total boost. The second CTLE stage acts as a fine adjustment on the total boost and impacts the shape of the boost curve accordingly. Larger settings correspond to higher total boost. The bandwidth of the CTLE can be adjusted using a 2-bit bandwidth control. Larger settings correspond to higher total bandwidth. For information on how to program the CTLE refer to the DS280BR820 Programming Guide.

In addition to high-frequency boost, the CTLE can apply wide-band amplitude gain. There are two settings (high-gain and low-gain) which work together with the driver DC gain control to affect the total input-to-output wide-band amplitude gain.