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ADA4938-1:  Ultralow Distortion Differential ADC Driver (Single)

Product Details

The ADA4938 is a low noise, ultralow distortion, high speed differential amplifier. It is an ideal choice for driving high performance ADCs with resolutions up to 16 bits from dc to 27 MHz, or up to 12 bits from dc to 74 MHz. The output common-mode voltage is adjustable over a wide range, allowing the ADA4938 to match the input of the ADC. The internal common-mode feedback loop also provides exceptional output balance as well as suppression of even-order harmonic distortion products.

Full differential and single-ended-to-differential gain configurations are easily realized with the ADA4938. A simple external feedback network of four resistors determines the closed-loop gain of the amplifier.

The ADA4938 is fabricated using the Analog Devices, Inc. proprietary third-generation, high voltage XFCB process, enabling it to achieve very low levels of distortion with an input voltage noise of only 2.6 nV/√Hz. The low dc offset and excellent dynamic performance of the ADA4938 make it well suited for a wide variety of data acquisition and signal processing applications.

The ADA4938-1 (single amplifier) is available in a Pb-free, 3 mm × 3 mm, 16-lead LFCSP. The ADA4938-2 (dual amplifier) is available in a Pb-free, 4 mm × 4 mm, 24-lead LFCSP. The pinouts have been optimized to facilitate layout and minimize distortion. The parts are specified to operate over the extended industrial temperature range of −40°C to +85°C.


  • ADC drivers
  • Single-ended-to-differential converters
  • IF and baseband gain blocks
  • Differential buffers
  • Line drivers
  • Data Sheet, Rev. 0, 11/07


    • Extremely low harmonic distortion
      −106 dBc HD2 @ 10 MHz
      −82 dBc HD2 @ 50 MHz
      −109 dBc HD3 @ 10 MHz
      −82 dBc HD3 @ 50 MHz
    • High speed
      −3 dB bandwidth of 1000 MHz, G = +1
      Slew rate: 4700 V/μs
      0.1 dB gain flatness to 150 MHz
      Fast overdrive recovery of 4 ns
    • Low input voltage noise: 2.6 nV/√Hz
    • 1 mV typical offset voltage
    • Externally adjustable gain
    • Differential-to-differential or single-ended-to-differential operation
    • Adjustable output common-mode voltage
    • Wide supply voltage range: +5 V to ±5 V
    • Single or dual amplifier configuration available

    Functional Block Diagram for ADA4938-1


    Title Content Type File Type
    ADA4938-1/ADA4938-2: Ultralow Distortion Differential ADC Driver Data Sheet (Rev A, 10/2009) (pdf, 655 kB) Data Sheets PDF
    AN-1026: High Speed Differential ADC Driver Design Considerations  (pdf, 355 kB) Application Notes PDF
    AN-0990: Terminating a Differential Amplifier in Single-Ended Input Applications  (pdf, 181 kB) Application Notes PDF
    AN-0992: Active Filter Evaluation Board for Differential Amplifiers  (pdf, 85 kB) Application Notes PDF
    AN-282: Fundamentals of Sampled Data Systems  (pdf, 2131 kB) Application Notes PDF
    AN-649: Using the Analog Devices Active Filter Design Tool  (pdf, 5301 kB) Application Notes PDF
    AN-584: Using the AD813X Differential Amplifier  (pdf, 174 kB)
    The AD813x differs from conventional op amps by the external presence of an additional input and output. The additional input, VOGM, controls the output common mode voltage.
    Application Notes PDF
    AN-589: Ways to Optimize the Performance of a Difference Amplifier  (pdf, 115 kB)
    This Application Note presents several ways to build and optimize the performance of a discrete difference amplifier. It also recommends amplifiers that will make the overall solution cost/performance competitive with monolithic instrument amplifiers.
    Application Notes PDF
    MT-218: Multiple Feedback Band-Pass Design Example  (pdf, 0) Tutorials PDF
    MT-076: Differential Driver Analysis  (pdf, 95 kB) Tutorials PDF
    MT-075: Differential Drivers for High Speed ADCs Overview  (pdf, 183 kB) Tutorials PDF
    A Stress-Free Method for Choosing High-Speed Op Amps
    A decision-tree approach to making the critical decision about high-speed op amp selection, including a look at some helpful tools.
    Webcasts WEBCAST
    UG-132: Evaluation Board User Guide for the ADA492x-1 and ADA493x-1 Family of Differential Amplifiers  (pdf, 226 kB)
    Differential Amplifier Evaluation Board for Single 16-lead 3 mm × 3 mm LFCSP Packages
    User Guides PDF
    Ask The Application Engineer 36, Wideband A/D Converter Front-End Design Considerations II: Amplifier-or Transformer Drive for the ADC?
    (Analog Dialogue, Volume 41 February 2007)
    Analog Dialogue HTML
    "Rules of the Road" for High-Speed Differential ADC Drivers
    (Analog Dialogue, Vol. 43, No. 5, 2009)
    Analog Dialogue HTML
    High Speed Amplifiers Selection Table  (pdf, 77 kB) Product Selection Guide PDF
    RF Source Booklet  (PDF, 4353 kB)
    RF IC Product Overview - Version P (02/2014)
    Overview PDF
    RAQs index Rarely Asked Questions HTML
    Glossary of EE Terms Glossary HTML

    Design Tools,Models,Drivers & Software

    Title Content Type File Type
    ADI DiffAmpCalc™
    ADI's new ADI DiffAmpCalc™ is a free, downloadable calculator for designing differential amplifier circuits. The tool is easy to use and features an interactive user interface to quickly get you up and running.
    ADIsim Design/Simulation Tools HTML
    ADA4938 SPICE Macro Model SPICE Models HTML

    Evaluation Kits & Symbols & Footprints

    Evaluation Boards & KitsView the Evaluation Boards and Kits page for documentation and purchasing

    Symbols and Footprints— Analog Devices offers Symbols & Footprints which are compatible with a large set of today’s CAD systems for broader and easier support.

    SampleSample & Buy

    Price, packaging, availability

    ADA4938-1 Model Options
    Model Package Pins Temp.
    Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
    ADA4938-1ACPZ-R2 Status: Production 16 ld LFCSP (3x3mm, 1.3mm exposed pad) 16 Ind Reel, 250 $4.70 $4.70 Y  Material Info PCN Purchase
    ADA4938-1ACPZ-R7 Status: Production 16 ld LFCSP (3x3mm, 1.3mm exposed pad) 16 Ind Reel, 1500 - $3.79 Y  Material Info PCN Purchase Sample
    ADA4938-1ACPZ-RL Status: Production 16 ld LFCSP (3x3mm, 1.3mm exposed pad) 16 Ind Reel, 5000 - $3.79 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.

    Evaluation board for evaluating the ADA4938-1
    Model Description Price RoHS View PCN/ PDN Check Inventory/
    ADA4938-1YCP-EBZ Status: Production 16-Lead LFCSP Bare Evaluation Board $18.25 Yes -
    ADA4938-1ACPZ-R7 Status: Production 16-Lead LFCSP - Yes -

    Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.

    Check Inventory & Purchase

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