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AD8123:  Triple Differential Receiver with Adjustable Line Equalization

Product Details

The AD8123 is a triple, high speed, differential receiver and equalizer that compensates for the transmission losses of UTP and coaxial cables up to 300 meters in length. Various gain stages are summed together to best approximate the inverse frequency response of the cable. Logic circuitry inside the AD8123 controls the gain functions of the individual stages so that the lowest noise can be achieved at short-to-medium cable lengths. This technique optimizes its performance for low noise, short-to-medium range applications, while at the same time provides the high gain bandwidth required for long cable equalization (up to 300 meters). Each channel features a high impedance differential input that is ideal for interfacing directly with the cable.

The AD8123 has three control pins for optimal cable compensation, as well as an output offset adjust pin. Two voltage-controlled pins are used to compensate for different cable lengths; the VPEAK pin controls the amount of high frequency peaking and the VGAIN pin adjusts the broadband flat gain, which compensates for the low frequency flat cable loss.

For added flexibility, an optional pole adjustment pin, VPOLE, allows movement of the pole locations, allowing for the compensation of different gauges and types of cable as well as variations between different cables and/or equalizers. The VOFFSET pin allows the dc voltage at the output to be adjusted, adding flexibility for dc-coupled systems.

The AD8123 is available in a 6 mm × 6 mm, 40-lead LFCSP and is rated to operate over the extended temperature range of −40°C to +85°C.


  • Keyboard-video-mouse (KVM)
  • Digital signage
  • RGB video over UTP cables
  • Professional video projection and distribution
  • HD video
  • Security video
  • Data Sheet, Rev. A, 11/07


    • Compensates cables to 300 meters for wideband video
    • Fast rise and fall times
      - 4.9 ns with 2 V step @ 150 meters of UTP cable
      - 8.0 ns with 2 V step @ 300 meters of UTP cable
    • 55 dB peak gain at 100 MHz
    • Two frequency response gain adjustment pins
      High frequency peaking adjustment (VPEAK)
      Broadband flat gain adjustment (VGAIN)
    • Pole location adjustment pin (VPOLE)
      Compensates for variations between cables
      Can be optimized for either UTP or coaxial cable
    • DC output offset adjust (VOFFSET)
    • Low output offset voltage: 24 mV
    • Compensates both RGB and YPbPr
    • Two on-chip comparators with hysteresis
      Can be used for common-mode sync extraction
    • Available in 40-lead, 6 mm × 6 mm LFCSP

    Functional Block Diagram for AD8123

    Complete Solutions for Video over UTP Signal Chain


    Title Content Type File Type
    AD8123: Triple Differential Receiver with Adjustable Line Equalization Data Sheet (Rev A, 11/2007) (pdf, 727 kB) Data Sheets PDF
    Video Amplifier Products (April 2007)  (pdf, 4117 kB) Overview PDF
    RAQs index Rarely Asked Questions HTML
    Glossary of EE Terms Glossary HTML

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    Price, packaging, availability

    AD8123 Model Options
    Model Package Pins Temp.
    Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
    AD8123ACPZ Status: Production 40 ld LFCSP (6x6mm w/4.3mm pad) 40 Ind Tray, 490 $8.90 $7.88 Y  Material Info PCN Purchase Sample
    AD8123ACPZ-R7 Status: Production 40 ld LFCSP (6x6mm w/4.3mm pad) 40 Ind Reel, 750 - $7.88 Y  Material Info PCN Purchase
    AD8123ACPZ-RL Status: Production 40 ld LFCSP (6x6mm w/4.3mm pad) 40 Ind Reel, 2500 - $7.88 Y  Material Info PCN Purchase
    Price Table Help

    The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

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