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AD8120:  Triple Skew-Compensating Video Delay Line with Analog and Digital Control

Product Details

The AD8120 is a triple broadband skew delay compensation IC that corrects for time mismatch of video signals incurred by transmission in unshielded twisted pairs of Category-5 and Category-6 type cables. Skew between the individual pairs exists in most types of multi-pair UTP cables due to the different twist-rates used for each pair in order to minimize crosstalk among the pairs. Some pairs are therefore longer than others, and in long cables, the difference in propagation time between two pairs can be well into the tens of nanoseconds.

The AD8120 contains three delay paths which provide broadband delays up to 50 nanoseconds, in 0.8 ns increments, using 64 digital control steps or analog control adjustment. The delay technique used in the AD8120 minimizes noise and offset at the outputs. It has a broad bandwidth that ranges between 106 MHz and 152 MHz, depending upon the delay setting. This high output bandwidth capability makes AD8120 ideal in applications that receive high-resolution video over UTP cables.

The logic circuitry inside the AD8120 provides for individual delay control of each path. The three delay times can be independently set using a standard four-wire SPI bus, standard I2C bus or by applying three analog control voltages to the VCR, VCG, and VCB pins. Analog control offers a simple solution for systems that do not have digital control available, the simplest being potentiometer control.

The AD8120 is designed to be used with the AD8123 triple UTP equalizer in video-over-UTP applications, but can be used in other applications where similar controllable broadband delays are required.

The AD8120 is available in a 5 mm × 5 mm 32-lead LFCSP package and is rated to operate over the industrial temperature range of -40°C to +85°C.


  • Keyboard-video-mouse (KVM)
  • Digital signage
  • RGB video over UTP cable
  • Professional video projection and distribution
  • HD video
  • Security video
  • General broadband delay lines
  • Data Sheet, Rev PrA, 10/2008


    • Corrects for unshielded twisted pair (UTP) cable delay skew
    • Delay of up to 50 ns per channel
    • High speed
      200 MHz BW @ VOUT = 1.4 V p-p and 0 ns delay
      150 MHz BW @ VOUT = 1.4 V p-p and 50 ns delay
    • Excellent channel-to-channel matching
      30 mV offset matching RTI
      0.8% gain matching
    • Low output offset
      ±30 mV RTI
      No external circuitry required to correct for offsets
    • Independent red, green, and blue delay controls
    • Drives 4 double-terminated video loads
    • Digital and analog delay control
      6-bit SPI bus
      I2C bus
      Analog voltage control
    • See data sheet for additional features

    Functional Block Diagram for AD8120

    Complete Solutions for Video over UTP Signal Chain

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    Price, packaging, availability

    AD8120 Model Options
    Model Package Pins Temp.
    Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
    AD8120ACPZ-R2 Status: Production 32 ld LFCSP (5x5mm) w/3.5mm exposed pad 32 Ind Reel, 250 $19.95 $19.95 Y  Material Info PCN Purchase
    AD8120ACPZ-R7 Status: Production 32 ld LFCSP (5x5mm) w/3.5mm exposed pad 32 Ind Reel, 1500 - $14.75 Y  Material Info PCN Purchase Sample
    AD8120ACPZ-RL Status: Production 32 ld LFCSP (5x5mm) w/3.5mm exposed pad 32 Ind Reel, 5000 - $14.75 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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