DS125BR820

ACTIVE

12-Gbps 8-channel linear redriver with equalization

Product details

Type Redriver Protocols 10G-KR, 10G-SR/LR, 40G-KR4, 40G-SR4/LR4, CPRI, Fibre Channel, General purpose, Infiniband, Interlaken, OBSAI, PCIe1, PCIe2, PCIe3, SAS1, SAS2, SAS3, SATA1, SATA2, SATA3, sRIO Applications Backplane, Front Port, Peripheral I/O Number of channels 8 Speed (max) (Gbpp) 12.5 Supply voltage (V) 2.5, 3.3 Rating Catalog Operating temperature range (°C) -40 to 85
Type Redriver Protocols 10G-KR, 10G-SR/LR, 40G-KR4, 40G-SR4/LR4, CPRI, Fibre Channel, General purpose, Infiniband, Interlaken, OBSAI, PCIe1, PCIe2, PCIe3, SAS1, SAS2, SAS3, SATA1, SATA2, SATA3, sRIO Applications Backplane, Front Port, Peripheral I/O Number of channels 8 Speed (max) (Gbpp) 12.5 Supply voltage (V) 2.5, 3.3 Rating Catalog Operating temperature range (°C) -40 to 85
WQFN (NJY) 54 55 mm² 10 x 5.5
  • Low 70 mW/Channel (Typ) Power Consumption,
    with Option to Power Down Unused Channels
  • Seamless Link Training Support
  • Enables Host ASIC to Meet Front-Port Eye Mask
    Requirements over Longer Reach
  • Advanced Configurable Signal Conditioning I/O
    • Receive CTLE up to 10 dB at 6 GHz
    • Linear Output Driver
    • Variable Output Voltage Range up to 1200
      mVp-p
  • Programmable via Pin Selection, EEPROM, or
    SMBus Interface
  • Single Supply Voltage: 2.5 V or 3.3 V
  • −40°C to 85°C Operating Temperature Range
  • Flow-Thru Layout in 10 mm × 5.5 mm 54-Pin
    Leadless WQFN Package
  • Low 70 mW/Channel (Typ) Power Consumption,
    with Option to Power Down Unused Channels
  • Seamless Link Training Support
  • Enables Host ASIC to Meet Front-Port Eye Mask
    Requirements over Longer Reach
  • Advanced Configurable Signal Conditioning I/O
    • Receive CTLE up to 10 dB at 6 GHz
    • Linear Output Driver
    • Variable Output Voltage Range up to 1200
      mVp-p
  • Programmable via Pin Selection, EEPROM, or
    SMBus Interface
  • Single Supply Voltage: 2.5 V or 3.3 V
  • −40°C to 85°C Operating Temperature Range
  • Flow-Thru Layout in 10 mm × 5.5 mm 54-Pin
    Leadless WQFN Package

The DS125BR820 is an extremely low-power high-performance repeater/redriver designed to support eight channels carrying high speed interface up to 12.5 Gbps, such as 40G-CR4, 40G-KR4, SAS/SATA, and PCIe. The receiver’s continuous time linear equalizer (CTLE) provides high frequency boost that is programmable from 3 to 10 dB at 6 GHz (12 Gbps) followed by a linear output driver. The CTLE receiver is capable of opening an input eye that is completely closed due to inter symbol interference (ISI) induced by interconnect medium such as board traces or twin axial-copper cables. The programmable equalization maximizes the flexibility of physical placement within the interconnect channel and improves overall channel performance.

When operating in 40G-CR4/KR4, SAS/SATA, and PCIe applications, the DS125BR820 preserves transmit signal characteristics, thereby allowing the host controller and the end point to negotiate transmit equalizer coefficients. This transparency in the link training protocol facilitates system level interoperability and minimizes latency.

The programmable settings can be applied easily via pin control, software (SMBus or I2C), or direct loading from an external EEPROM. In EEPROM mode, the configuration information is automatically loaded on power up, thereby eliminating the need for an external microprocessor or software driver.

The DS125BR820 is an extremely low-power high-performance repeater/redriver designed to support eight channels carrying high speed interface up to 12.5 Gbps, such as 40G-CR4, 40G-KR4, SAS/SATA, and PCIe. The receiver’s continuous time linear equalizer (CTLE) provides high frequency boost that is programmable from 3 to 10 dB at 6 GHz (12 Gbps) followed by a linear output driver. The CTLE receiver is capable of opening an input eye that is completely closed due to inter symbol interference (ISI) induced by interconnect medium such as board traces or twin axial-copper cables. The programmable equalization maximizes the flexibility of physical placement within the interconnect channel and improves overall channel performance.

When operating in 40G-CR4/KR4, SAS/SATA, and PCIe applications, the DS125BR820 preserves transmit signal characteristics, thereby allowing the host controller and the end point to negotiate transmit equalizer coefficients. This transparency in the link training protocol facilitates system level interoperability and minimizes latency.

The programmable settings can be applied easily via pin control, software (SMBus or I2C), or direct loading from an external EEPROM. In EEPROM mode, the configuration information is automatically loaded on power up, thereby eliminating the need for an external microprocessor or software driver.

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Technical documentation

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Top documentation Type Title Format options Date
* Data sheet DS125BR820 Low-Power 12.5 Gbps 8-Channel Linear Repeater datasheet (Rev. B) PDF | HTML 06 Feb 2015
Application note Extend reach with Ethernet Redrivers and Retimers for 10G-12.5G Applications (Rev. A) 31 Jan 2023
Technical article Eye doctor: Why too much equalization boost is bad for your serial link health PDF | HTML 13 Jun 2016
Technical article SigCon Architect: The keys to your high-speed design PDF | HTML 27 Oct 2015
Application note Linear Repeaters Used in SAS/SATA Applications PDF | HTML 21 Sep 2015
Technical article IBIS-AMI channel simulations made simple through WEBENCH Interface Designer PDF | HTML 07 Aug 2015
Analog Design Journal Advanced linear equalization in multi-gigabit systems 28 Apr 2015
Analog Design Journal Analog Applications Journal 2Q 2015 28 Apr 2015
Application note Channel Tuning Made Easy Using Linear Repeaters for 10G and 12G Applications 20 Jan 2015
Application note Understanding EEPROM Programming for High Speed Repeaters and Mux Buffers 09 Oct 2014
Application note Advanced Linear Repeater Used in PCIe 3.0 Add-in Card Compliance Environment 02 Oct 2014
Application note DS125BR820 Linear Repeater Used in 40GbE nPPI / SFF-8431 Applications 09 Aug 2014

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

DS125BR820EVM — DS125BR820EVM: 12.5 Gbps 8-Channel Repeater with Equalization Evaluation Module

The DS125BR820EVM – SMA evaluation kit provides a complete high bandwidth platform to evaluate the 40GbE, PCIe, and SAS/SATA signal conditioning features of the Texas Instruments DS125BR820 repeater/redriver. The DS125BR820EVM can be used for standard compliance testing, performance evaluation, and (...)

User guide: PDF
Not available on TI.com
Support software

SIGCONARCHITECT SigCon Architect v2.0.0.8

Our SigCon Architect utility tool provides a simple-to-use and robust system for interaction with several different high-speed signal conditioning TI devices. This software provides an interactive GUI for supported devices to access device features through SMBus and SPI communications.

SigCon (...)

Supported products & hardware

Supported products & hardware

Support software

SIGCONARCHITECT-WRTE SigCon Architect With RTE v2.0.0.8

Supported products & hardware

Supported products & hardware

Simulation model

12G Linear EQ IBIS-AMI Model

SNLM280.ZIP (11362 KB) - IBIS-AMI Model
Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
Simulation tool

TINA-TI — SPICE-based analog simulation program

TINA-TI provides all the conventional DC, transient and frequency domain analysis of SPICE and much more. TINA has extensive post-processing capability that allows you to format results the way you want them. Virtual instruments allow you to select input waveforms and probe circuit nodes voltages (...)
User guide: PDF
Reference designs

TIDA-00417 — 2-port 40GbE/10GbE QSFP+ Signal Conditioner Reference Design

This verified reference design is a signal conditioning solution for front-port QSFP+ supporting two 40GbE ports compatible with 40G-CR4/SR4/LR4 and 10G SFF-8431 requirements. The design is applicable to optical and passive/active copper cables. It allows for reach extension between the Switch ASIC (...)
User guide: PDF
Schematic: PDF
Package Pins CAD symbols, footprints & 3D models
WQFN (NJY) 54 Ultra Librarian

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