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 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
Features and Benefits
  • 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
    • Analog to Digital Converters
    Design Tools
    Data Sheets
    Documentnote
    AD7794/AD7795: 6-Channel, Low Noise, Low Power, 24-/16-Bit Sigma Delta ADC with On-Chip In-Amp and Reference Data Sheet (Rev. D)PDF 807 kB
    Application Notes
    Documentnote
    AN-202: An IC Amplifier User’s Guide to Decoupling, Grounding, and Making Things Go Right for a Change (Rev. B)PDF 76.97 K
    AN-389: Using Sigma-Delta Converters-Part 2PDF 590 kB
    AN-388: Using Sigma-Delta Converters-Part 1PDF 590 kB
    AN-880: ADC Requirements for Temperature Measurement Systems (Rev. 0)PDF 423 kB
    AN-347: Shielding and GuardingPDF 688 kB
    AN-968: Current Sources: Options and Circuits (Rev. 0)PDF 131 kB
    AN-311: How to Reliably Protect CMOS Circuits Against Power Supply OvervoltagingPDF 217 kB
    AN-607: Selecting a Low Bandwidth (<15 kSPS) Sigma-Delta ADC (Rev. E)PDF 222 kB
    AN-615: Peak-to-Peak Resolution Versus Effective Resolution (Rev. 0)PDF 70 kB
    AN-101: Cross Plot Generator Allows Quick A/D Converter EvaluationPDF 280 kB
    AN-397: Electrically Induced Damage to Standard Linear Integrated Circuits:PDF 149 kB
    AN-283: Sigma-Delta ADCs and DACsPDF 1699 kB
    Product Highlight
    Documentnote
    ICs for Programmable Logic Control and Distributed Control SystemsPDF 976.19 K
    Frequently Asked Questions
    Documentnote
    Order Information
    Part NumberPackagePacking QtyTemp RangePrice 100-499Price 1000+RoHS
    AD7794BRU Production24 ld TSSOPOTH 62-40 to 105C7.976.78N
    AD7794BRUZ Production24 ld TSSOPOTH 62-40 to 105C6.95.87Y
    AD7794BRUZ-REEL Production24 ld TSSOPREEL 2500-40 to 105C05.87Y
    AD7794CRUZ Production24 ld TSSOPOTH 62-40 to 125C7.466.38Y
    AD7794CRUZ-REEL Production24 ld TSSOPREEL 2500-40 to 125C06.38Y
    Evaluation Boards
    Part NumberDescriptionPriceRoHS
    EVAL-AD7794EBZEvaluation Board59Y
    AD7794/AD7795: 6通道、低噪声、低功率24/16位Σ-Δ型ADC，内置片内仪表放大器和基准电压源数据手册 (Rev. D) ad7794
    AD7794/AD7795: 6-Channel, Low Noise, Low Power, 24-/16-Bit Sigma Delta ADC with On-Chip In-Amp and Reference Data Sheet (Rev. D) ad7794
    AD7785/AD7790/AD7791/AD7792/AD7793/AD7794/AD7795/AD7796/AD7797/AD7798/AD7799 Digital Filter Model ad7790
    AD7794参考代码 ad7794
    AN-202: An IC Amplifier User’s Guide to Decoupling, Grounding, and Making Things Go Right for a Change (Rev. B) ad7715
    AN-389: Using Sigma-Delta Converters-Part 2 ad7715
    AN-388: Using Sigma-Delta Converters-Part 1 ad7715
    AN-880: ADC Requirements for Temperature Measurement Systems (Rev. 0) ad7792
    AN-347: Shielding and Guarding ad677
    AN-397: 标准线性集成电路的电诱发损坏 (Rev. 0) ad7715
    AN-101: 交会图发生器加快模数转换器评估 (Rev. 0) ad677
    AN-880: 温度测量系统对ADC的要求 (Rev. 0) ad7792
    AN-615: 峰峰值分辨率与有效分辨率 (Rev. 0) ad7715
    AN-607: 选择低带宽(<15kSPS)Σ-Δ型ADC (Rev. E) ad7701
    AN-202: IC放大器用户指南：去耦、接地及其他一些要点 (Rev. 0) ad8021
    AN-968: 电流源：方案与电路 (Rev. 0) ad7783
    AN-968: Current Sources: Options and Circuits (Rev. 0) ad7783
    AN-311: How to Reliably Protect CMOS Circuits Against Power Supply Overvoltaging ad1674
    AN-607: Selecting a Low Bandwidth (<15 kSPS) Sigma-Delta ADC (Rev. E) ad7701
    AN-615: Peak-to-Peak Resolution Versus Effective Resolution (Rev. 0) ad7715
    AN-101: Cross Plot Generator Allows Quick A/D Converter Evaluation ad677
    AN-397: Electrically Induced Damage to Standard Linear Integrated Circuits: ad7715
    AN-311: 如何切实有效地保护CMOS电路不受电源过压影响 (Rev. 0) adg406
    AN-389: 使用Σ-Δ转换器—第二部分[中文版] (Rev. 0) ad7715
    AN-388: 使用Σ-Δ转换器—第一部分[中文版] (Rev. 0) ad7715
    AN-283: Σ-Δ型ADC和DAC[中文版] (Rev. 0) ad74111
    AN-283: Sigma-Delta ADCs and DACs ad7715
    ICs for Programmable Logic Control and Distributed Control Systems ad7794
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