AD7798:  3-Channel, Low Noise, Low Power, 16-Bit, Sigma Delta ADC with On-Chip In-Amp

The AD7798/AD7799 are low power, low noise, complete analog front ends for high precision measurement applications. The AD7798/AD7799 contains a low noise, 16-/24-bit Σ-Δ ADC with three ...More

AD7798:  3-Channel, Low Noise, Low Power, 16-Bit, Sigma Delta ADC with On-Chip In-Amp

Product Description

The AD7798/AD7799 are low power, low noise, complete analog front ends for high precision measurement applications. The AD7798/AD7799 contains a low noise, 16-/24-bit Σ-Δ ADC with three differential analog inputs. The on-chip, low noise instrumentation amplifier means that signals of small amplitude can be interfaced directly to the ADC. With a gain setting of 64, the rms noise is 27 nV for the AD7799 and 40 nV for the AD7798 when the update rate equals 4.17 Hz.

On-chip features include a low-side power switch, reference detect, programmable digital output pins, burnout currents, and an internal clock oscillator. The output data rate from the part is software-programmable and can be varied from 4.17 Hz to 470 Hz.

The part operates with a power supply from 2.7 V to 5.25 V. The AD7798 consumes a current of 300 μA typical, whereas the AD7799 consumes 380 μA typical. Both devices are housed in a 16-lead TSSOP package.

Applications

  • Weigh scales
  • Pressure measurement
  • Strain gauge transducers
  • Gas analysis
  • Industrial process control
  • Instrumentation
  • Portable instrumentation
  • Blood analysis
  • Smart transmitters
  • Liquid/gas chromotography 6-digit DVM
  • Data Sheet, Rev. A, 3/07

    Features

    • RMS noise:
      27 nV at 4.17 Hz (AD7799)
      65 nV at 16.7 Hz (AD7799)
      40 nV at 4.17 Hz (AD7798)
      85 nV at 16.7 Hz (AD7798)
    • Current: 380 μA typical
    • Power-down: 1 μA maximum
    • Update rate: 4.17 Hz to 470 Hz 3 differential inputs
    • Low noise, programmable gain, instrumentation amp
    • Internal clock oscillator
    • Simultaneous 50 Hz/60 Hz rejection
    • Reference detect
    • Low-side power switch
    • Programmable digital outputs
    • Burnout currents
    • Power supply: 2.7 V to 5.25 V

    Diagrams

    AD7798 Diagram
    Functional Block Diagram for AD7798

    Specifications

    Resolution (Bits) 16bit
    T-Put Rate 470SPS
    # Chan 3
    Supply V Multi(+3, +5),Multi(+3.3, +5),Single(+2.7 to +5.25) ,Single(+3),Single(+3.3),Single(+5)
    Pwr Diss (max) 2mW
    Interface Ser,SPI
    Ain Range (2Vref/PGA Gain) p-p
    SNR (dB) n/a
    Pkg Type SOP

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    Part# Res Throughput Rate # of Inputs Operating Pwr Diss
    AD7798 16 470SPS 3 2mW
    AD7792 16 470SPS 3 2.5mW
    AD7707 16 500SPS 3 3.75mW
    AD7706 16 500SPS 3 6.5mW
    AD7450 12 1MSPS 1 1.3mW
    AD7466 12 200KSPS 1 900µW
    AD7467 10 200KSPS 1 630µW
    AD7468 8 200KSPS 1 570µW
    AD7705 16 500SPS 2 6.5mW
    AD974 16 200KSPS 4 120mW
    AD7654 16 500KSPS 4 135mW
    Pricing, Packaging & Availability

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    Status
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    • Pre-Release: The model has not been released to general production, but samples may be available.
    • Production: The model is currently being produced, and generally available for purchase and sampling.
    • Last Time Buy: The model has been scheduled for obsolescence, but may still be purchased for a limited time.
    • Obsolete: The specific part is obsolete and no longer available. Other models listed in the table may still be available (if they have a status that is not obsolete).
    Package Description
    The package for this IC (i.e. DIP, SOIC, BGA). An Evaluation Board is a board engineered to show the performance of the model, the part is included on the board.

    For detailed drawings and chemical composition please consult our  Package Site

    Pin Count
    Pin Count is the number of pins, balls, or pads on the device. Pin-out diagrams & pin function descriptions may be found in the datasheet.

    Temperature Range
    This is the acceptable operating range of the device. The various ranges specified are as follows:
    • Commercial: 0 to +70 degrees Celsius
    • Military : -55 to +125 degrees Celsius
    • Industrial: Temperature ranges may vary by model. Please consult the datasheet for more information.
    • Automotive: -40 to +125 degrees Celsius
    Price
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    RoHS Compliant
    Due to environmental concerns, ADI offers many of our products in lead-free versions. For more information about lead-free parts, please consult our Pb (Lead) free information page.

    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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