SNLA236 September   2015 DS125BR111 , DS125BR401A , DS125BR820

 

  1.   Linear Repeaters Used in SAS/SATA Applications
    1.     Trademarks
    2. 1 Introduction
    3. 2 SAS-3 Transmit Waveforms
      1. 2.1 Default Transmit Equalization Coefficients
      2. 2.2 Using Linear Equalization to Recover Tx FIR Information
      3. 2.3 Linear Equalization Effects on Jitter Due to Attenuation
    4. 3 Equalizer Placement within a SAS-3 Channel
    5. 4 System Results Using Linear Equalization
      1. 4.1 Linear Equalization Effects on Jitter Due to Attenuation
      2. 4.2 Channel Extension
    6. 5 Passing Out Of Band (OOB) Signals
    7. 6 Conclusions
    8. 7 Appendix A: Layout Considerations
  2.   Revision History

1 Introduction

The testing carried out in this report involves the DS125BR820 Low-Power 12.5Gbps 8-Channel Linear Repeater which is designed to support 40GbE (40G-CR4/KR4/SR4/LR4), SAS/SATA, and PCIe Gen 3.0 applications. The linear nature of the DS125BR820’s equalization allows the DS125BR820 to preserve the transmit signal characteristics of the system ASIC, thereby allowing the link partners to negotiate transmit equalizer coefficients.

The DS125BR820 is in a small 10mm x 5.5mm leadless WQFN package, which fits easily behind a standard miniSAS-HD connector.

A typical SAS application of the DS125BR820 is shown in Figure 1.

typical_application_ds125br820_snla236.gifFigure 1. Typical Application Using the DS125BR820