SNLS450A January   2014  – June 2015 DS125DF111

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 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 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
        1. 7.3.1.1 Input Channel Equalization
        2. 7.3.1.2 Clock and Data Recovery
        3. 7.3.1.3 PRBS Pattern Generator
        4. 7.3.1.4 Datapath Multiplexer and Output Driver
        5. 7.3.1.5 Reference Clock
        6. 7.3.1.6 Control Pins
          1. 7.3.1.6.1 Pin Mode Limitation
        7. 7.3.1.7 Eye Opening Monitor
    4. 7.4 Device Functional Modes
      1. 7.4.1 Control Pin Mode
      2. 7.4.2 SMBus Master Mode and SMBus Slave Mode
    5. 7.5 Programming
      1. 7.5.1 SMBus Interface
        1. 7.5.1.1  Address Lines
        2. 7.5.1.2  Device Configuration in SMBus Slave Mode
        3. 7.5.1.3  Bit Fields in the Register Set
        4. 7.5.1.4  Writing To and Reading from the Control/Shared Registers
        5. 7.5.1.5  SMBus Strap Observation
        6. 7.5.1.6  Interrupt Channel Flag Bits
        7. 7.5.1.7  Control/Shared Register Reset
        8. 7.5.1.8  Device Revision and Device ID
        9. 7.5.1.9  Channel Select Register
        10. 7.5.1.10 Resetting Individual Channels of the Retimer
        11. 7.5.1.11 Rate and Subrate Setting
        12. 7.5.1.12 Overriding the CTLE Boost Setting
        13. 7.5.1.13 Overriding the Output Multiplexer
        14. 7.5.1.14 Overriding the VCO Divider Selection
        15. 7.5.1.15 Using the Internal Eye Opening Monitor
        16. 7.5.1.16 Overriding the DFE Tap Weights and Polarities
        17. 7.5.1.17 Enabling Slow Rise/Fall Time on the Output Driver
        18. 7.5.1.18 Using the PRBS Generator
        19. 7.5.1.19 Inverting the Output Polarity
        20. 7.5.1.20 Figure of Merit Adaption
        21. 7.5.1.21 Setting the Rate and Subrate for Lock Acquisition
        22. 7.5.1.22 Setting the Adaption/Lock Mode
        23. 7.5.1.23 Initiating Adaption
        24. 7.5.1.24 Overriding the CTLE Settings Used for CTLE Adaption
        25. 7.5.1.25 Setting the Output Differential Voltage
        26. 7.5.1.26 Setting the Output De-Emphasis Setting
        27. 7.5.1.27 CTLE Setting for Divide by 4 and Divide by 8 VCO Ranges
    6. 7.6 Register Maps
      1. 7.6.1 Reading To and Writing from the Channel 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
      3. 8.2.3 Application Curves
        1. 8.2.3.1 SFF-8431 Testing
  9. 9 Power Supply Recommendations
  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 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

1 Features

  • Pin Compatible Retimer Family
    • DS110DF111 with DFE: 8.5 - 11.3 Gbps
    • DS125DF111 with DFE: 9.8 - 12.5 Gbps
  • Adaptive CTLE: 33 dB Max Boost at 6.25 GHz
  • Self Tuning 5-Tap DFE
  • Raw Equalized and Retimed Data Loopback
  • Adjustable Transmit VOD: 600 to 1300 mVp-p
  • Settable Tx De-Emphasis Driver 0 to –12dB
  • Low Power Consumption: 220 mW/Channel
  • Locks to Half/Quarter/Eighth Data Rates for Legacy Support
  • On-Chip Eye Monitor (EOM), PRBS Generator
  • Input Signal Detection, CDR Lock Detection/Indicator
  • Single 3.3-V or 2.5-V Power Supply
  • SMBus, EEPROM, or Pin Based Configuration
  • 4-mm x 4-mm, 24-Pin WQFN Package
  • Operating Temp Range: –40°C to 85°C

2 Applications

  • Front Port Optical Interconnects
  • SFF-8431
  • 10G/1G Ethernet
  • CPRI

3 Description

The DS125DF111 is a dual channel (1-lane bidirectional) retimer with integrated signal conditioning. The DS125DF111 includes an input Continuous-Time Linear Equalizer (CTLE), clock and data recovery (CDR) and transmit driver on each channel.

The DS125DF111 with its on-chip Decision Feedback Equalizer (DFE) can enhance the reach and robustness of long, lossy, cross-talk-impaired high speed serial links to achieve BER < 1x10–15. For less demanding applications/interconnects, the DFE can be switched off and achieve the same BER performance. The DS125DF111 and DS110DF111 devices are pin-compatible.

Each channel of the DS125DF111 independently locks to specific serial data at data rates from 9.8 to 12.5 Gbps or to any supported sub-rate of these data rates. This simplifies system design and lowers overall cost.

Programmable transmit de-emphasis driver offers precise settings to meet the SFF-8431 output eye template. The fully adaptive receive equalization (CTLE and DFE) enables longer distance transmission in lossy copper interconnect and backplanes with multiple connectors. The CDR function is ideal for use in front port parallel optical module applications to reset the jitter budget and retime high speed serial data.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
DS125DF111 WQFN (24) 4.0 mm × 4.0 mm
  1. For all available packages, see the orderable addendum at the end of the datasheet.

Typical Application

DS125DF111 SimplifiedSchematic_125_r1.gif