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AD7794:  6-Channel, Low Noise, Low Power, 24-Bit Sigma Delta ADC with On-Chip In-Amp and Reference

The AD7794/AD7795 are low power, low noise, complete analog front ends for high precision measurement applications. They contain a low noise, 24-/16-bit Σ-Δ ADC with six differential inputs. The on-chip low noise instrumentation amplifier means that signals of small amplitude can be interfaced directly to the ADC.

Each device contains a precision, low noise, low drift internal ...More

AD7794:  6-Channel, Low Noise, Low Power, 24-Bit Sigma Delta ADC with On-Chip In-Amp and Reference

Product Description

The AD7794/AD7795 are low power, low noise, complete analog front ends for high precision measurement applications. They contain a low noise, 24-/16-bit Σ-Δ ADC with six differential inputs. The on-chip low noise instrumentation amplifier means that signals of small amplitude can be interfaced directly to the ADC.

Each device contains a precision, low noise, low drift internal band gap reference, and can also accept up to two external differential references. Other on-chip features include programmable excitation current sources, burnout currents, and a bias voltage generator that is used to set the common-mode voltage of a channel to AVDD/2. The low-side power switch can be used to power down bridge sensors between conversions, minimizing the system’s power consumption. The AD7794/AD7795 can operate with either an internal clock or an external clock. The output data rate from each part can vary from 4.17 Hz to 470 Hz.

Both parts operate with a power supply from 2.7 V to 5.25 V. The B-grade parts (AD7794 and AD7795) are specified for a temperature range of −40°C to +105°C while the C-grade part (AD7794) is specified for a temperature range of −40°C to +125°C. They consume a current of 400 μA typical and are housed in a 24-lead TSSOP.

Applications

  • Temperature measurement
  • Pressure measurement
  • Weigh scales
  • Strain gage transducers
  • Gas analysis

    • Data Sheet, Rev. D, 3/07

    RESOURCES & TOOLS

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    • Up to 23 effective bits
    • RMS noise: 40 nV @ 4.17 Hz, 85 nV @ 16.7 Hz
    • Current: 400 μA typical
    • Power-down: 1 μA maximum
    • Low noise, programmable gain, instrumentation amp
    • Band gap reference with 4 ppm/°C drift typical
    • Update rate: 4.17 Hz to 470 Hz
    • Six differential analog inputs
    • Internal clock oscillator
    • Simultaneous 50 Hz/60 Hz rejection
    • Reference detect
    • Programmable current sources
    • Resolution (Bits): 24bit
    • T-Put Rate: 470SPS
    • # Chan: 6
    • Supply V: Multi(+3, +5),Multi(+3.3, +5),Single(+2.7 to +5.25) ,Single(+2.7),Single(+3),Single(+3.3),Single(+5)
    • Pwr Diss: 2.5mW
    • Interface: Ser,SPI
    • Ain Range: (2Vref/PGA Gain) p-p
    • SNR (dB): n/a
    • Pkg Type: SOP

    Functional Block Diagram for AD7794

    Of Note ...

    Similar Products

    arrow View Full Interactive Product Selection Table
    Part# Bits Throughput Rate # of Inputs Operating Pwr Diss
    AD7794 24 470SPS 6 2.5mW
    AD7793 24 470SPS 3 2.5mW
    AD7799 24 470SPS 3 2.5mW
    AD7795 16 470SPS 6 2.5mW
    AD7889 12 105KSPS 6 2.3mW
    AD7879 12 105KSPS 6 2.3mW
    AD7785 20 470SPS 3 2.5mW
    AD7798 16 470SPS 3 2mW
    AD7792 16 470SPS 3 2.5mW
    AD7714 24 1KSPS 5 7mW
    AD7190 24 4.8KSPS 5 36.8mW
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    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.

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    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
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    *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.
    **Sample availability may be better than production availability. Please enter samples into your cart to check sample availability.