SNLS647G december   2019  – july 2023 DP83826E , DP83826I

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Mode Comparison Tables
  7. 6 Pin Configuration and Functions (ENHANCED Mode)
  8. 7 Pin Configuration and Functions (BASIC Mode)
  9. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Timing Requirements
    7. 8.7 Timing Diagrams
    8. 8.8 Typical Characteristics
  10. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1  Auto-Negotiation (Speed/Duplex Selection)
      2. 9.3.2  Auto-MDIX Resolution
      3. 9.3.3  Energy Efficient Ethernet
        1. 9.3.3.1 EEE Overview
        2. 9.3.3.2 EEE Negotiation
      4. 9.3.4  EEE for Legacy MACs Not Supporting 802.3az
      5. 9.3.5  Wake-on-LAN Packet Detection
        1. 9.3.5.1 Magic Packet Structure
        2. 9.3.5.2 Magic Packet Example
        3. 9.3.5.3 Wake-on-LAN Configuration and Status
      6. 9.3.6  Low Power Modes
        1. 9.3.6.1 Active Sleep
        2. 9.3.6.2 IEEE Power-Down
        3. 9.3.6.3 Deep Power Down State
      7. 9.3.7  RMII Repeater Mode
      8. 9.3.8  Clock Output
      9. 9.3.9  Media Independent Interface (MII)
      10. 9.3.10 Reduced Media Independent Interface (RMII)
      11. 9.3.11 Serial Management Interface
        1. 9.3.11.1 Extended Register Space Access
        2. 9.3.11.2 Write Address Operation
        3. 9.3.11.3 Read Address Operation
        4. 9.3.11.4 Write (No Post Increment) Operation
        5. 9.3.11.5 Read (No Post Increment) Operation
        6. 9.3.11.6 Example Write Operation (No Post Increment)
      12. 9.3.12 100BASE-TX
        1. 9.3.12.1 100BASE-TX Transmitter
          1. 9.3.12.1.1 Code-Group Encoding and Injection
          2. 9.3.12.1.2 Scrambler
          3. 9.3.12.1.3 NRZ to NRZI Encoder
          4. 9.3.12.1.4 Binary to MLT-3 Converter
        2. 9.3.12.2 100BASE-TX Receiver
      13. 9.3.13 10BASE-Te
        1. 9.3.13.1 Squelch
        2. 9.3.13.2 Normal Link Pulse Detection and Generation
        3. 9.3.13.3 Jabber
        4. 9.3.13.4 Active Link Polarity Detection and Correction
      14. 9.3.14 Loopback Modes
        1. 9.3.14.1 Near-end Loopback
        2. 9.3.14.2 MII Loopback
        3. 9.3.14.3 PCS Loopback
        4. 9.3.14.4 Digital Loopback
        5. 9.3.14.5 Analog Loopback
        6. 9.3.14.6 Far-End (Reverse) Loopback
      15. 9.3.15 BIST Configurations
      16. 9.3.16 Cable Diagnostics
        1. 9.3.16.1 Time Domain Reflectometry (TDR)
        2. 9.3.16.2 Fast Link-Drop Functionality
      17. 9.3.17 LED and GPIO Configuration
    4. 9.4 Programming
      1. 9.4.1 Hardware Bootstraps Configuration
        1. 9.4.1.1 DP83826 Bootstrap Configurations (ENHANCED Mode)
          1. 9.4.1.1.1 Bootstraps for PHY Address
        2. 9.4.1.2 DP83826 Strap Configuration (BASIC Mode)
          1. 9.4.1.2.1 Bootstraps for PHY Address
    5. 9.5 Register Maps
      1. 9.5.1 DP83826 Registers
  11. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 Twisted-Pair Interface (TPI) Network Circuit
      2. 10.2.2 Transformer Recommendations
      3. 10.2.3 Capacitive DC Blocking
      4. 10.2.4 Design Requirements
        1. 10.2.4.1 Clock Requirements
          1. 10.2.4.1.1 Oscillator
          2. 10.2.4.1.2 Crystal
      5. 10.2.5 Detailed Design Procedure
        1. 10.2.5.1 MII Layout Guidelines
        2. 10.2.5.2 RMII Layout Guidelines
        3. 10.2.5.3 MDI Layout Guidelines
      6. 10.2.6 Application Curves
  12. 11Power Supply Recommendations
  13. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 Signal Traces
      2. 12.1.2 Return Path
      3. 12.1.3 Transformer Layout
      4. 12.1.4 Metal Pour
      5. 12.1.5 PCB Layer Stacking
        1. 12.1.5.1 Layout Example
  14. 13Device and Documentation Support
    1. 13.1 Related Documentation
    2. 13.2 Receiving Notification of Documentation Updates
    3. 13.3 Support Resources
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Glossary
  15. 14Mechanical, Packaging, and Orderable Information

Package Options

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

9.3.16.1 Time Domain Reflectometry (TDR)

The DP83826 uses TDR to determine the quality of the cables, connectors and terminations in addition to estimating the cable length. Some of the possible problems that can be diagnosed include opens, shorts, cable impedance mismatch, bad connectors, termination mismatches, cross faults, cross shorts and any other discontinuities along the cable.

The DP83826 transmits a test pulse of known amplitude (1 V) down each of the two pairs of an attached cable. The transmitted signal continues down the cable and reflects from each cable imperfection, fault, connector and from the end of the cable itself. After the pulse transmission, the DP83826 measures the return time and amplitude of all these reflected pulses. This technique enables measuring the distance and magnitude (impedance) of non-terminated cables (open or short), discontinuities (bad connectors) and improperly terminated cables with ±1-m accuracy.

For all TDR measurements, the transformation between time of arrival and physical distance is done by the external host using minor computations (such as multiplication, addition and lookup tables). The host must know the expected propagation delay of the cable, which depends, among other things, on the cable category (for example, CAT5, CAT5e, or CAT6).

TDR measurement is allowed in the following scenarios:

  • While the link partner is disconnected – cable is unplugged at the other side
  • Link partner is connected but remains “quiet” (for example, in power down mode)
  • TDR could be automatically activated when the link fails or is dropped

TDR Auto-Run can be enabled by using bit[8] in the Control Regsiter #1 (CR1, address 0x0009). When a link-drops, TDR automatically executes and stores the results in the respective TDR Cable Diagnostic Location Result Registers #1 - #5 (CDLRR, addresses 0x0180 to 0x0184) and the Cable Diagnostic Amplitude Result Registers #1 - #5 (CDLAR, addresses 0x0185 to 0x0189). TDR can also be run manually using bit[15] in the Cable Diagnostic Control Register (CDCR, address 0x001E). Cable diagnostic status is obtained by reading bits[1:0] in the CDCR. Additional TDR functions including cycle averaging and crossover disable can be found in the Cable Diagnostic Specific Control Register (CDSCR, address 0x0170). Refer to the application report Time Domain Reflectometry with DP83826 for details.