AD7731 Low Noise, High Throughput 24-Bit Sigma-Delta ADC

The part features three buffered differential programmable gain analog inputs (which can be configured as five pseudo-differential inputs), as well as a differential reference input. The part operates from a single +5 V supply and accepts seven unipolar analog input ranges: 0 to +20 mV, +40 mV, +80 mV, +160 mV, +320 mV, +640 mV and +1.28 V, and seven bipolar ranges: ±20 mV, ±40 mV, ±80 mV, ±160 mV, ±320 mV, ±640 mV and ±1.28 V. The peak-to-peak resolution achievable directly from the part is 16 bits at an 800 Hz output rate. The part can switch between channels with 1 ms settling time and maintain a performance level of 13 bits of peak-to-peak resolution. The serial interface on the part can be configured for three-wire operation and is compatible with microcontrollers and digital signal processors. The AD7731 contains self-calibration and system calibration options and features an offset drift of less than 5 nV/°C and a gain drift of less than 2 ppm/°C. The part is available in a 24-lead plastic DIP, a 24-lead SOIC and 24-lead TSSOP package. Applications Process Control PLCs/DCS Industrial Instrumentation

The AD7731 is a complete analog front-end for process control applications. The device has a proprietary programmable gain front end that allows it to accept a range of input signal ranges, including low level signals, directly from a transducer. The sigmadelta architecture of the part consists of an analog modulator and a low pass programmable digital filter, allowing adjustment of filter cutoff, output rate and settling time.

The part features three buffered differential programmable gain analog inputs (which can be configured as five pseudo-differential inputs), as well as a differential reference input. The part operates from a single +5 V supply and accepts seven unipolar analog input ranges: 0 to +20 mV, +40 mV, +80 mV, +160 mV, +320 mV, +640 mV and +1.28 V, and seven bipolar ranges: ±20 mV, ±40 mV, ±80 mV, ±160 mV, ±320 mV, ±640 mV and ±1.28 V. The peak-to-peak resolution achievable directly from the part is 16 bits at an 800 Hz output rate. The part can switch between channels with 1 ms settling time and maintain a performance level of 13 bits of peak-to-peak resolution.

The serial interface on the part can be configured for three-wire operation and is compatible with microcontrollers and digital signal processors. The AD7731 contains self-calibration and system calibration options and features an offset drift of less than 5 nV/°C and a gain drift of less than 2 ppm/°C.

The part is available in a 24-lead plastic DIP, a 24-lead SOIC and 24-lead TSSOP package.

Applications
  • Process Control
  • PLCs/DCS
  • Industrial Instrumentation
Features and Benefits
  • 24-Bit Sigma-Delta ADC
  • 16 Bits p-p Resolution at 800 Hz Output Rate
  • Programmable Output Rates up to 6.4 kHz
  • Programmable Gain Front End
  • ±0.0015% Nonlinearity
  • Buffered Differential Inputs
  • Programmable Filter Cutoffs
  • FASTStep™* Mode for Channel Sequencing
  • Single Supply Operation
Analog to Digital Converters
Design Tools
Data Sheets
Documentnote
AD7731: Low Noise, High Throughput 24-Bit Sigma-Delta ADC Data Sheet (Rev. A)PDF 411 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-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-397: Electrically Induced Damage to Standard Linear Integrated Circuits:PDF 149 kB
AN-283: Sigma-Delta ADCs and DACsPDF 1699 kB
Order Information
Part NumberPackagePacking QtyTemp RangePrice 100-499Price 1000+RoHS
AD7731BNZ Production24 ld PDIPOTH 15-40 to 85C13.711.65Y
AD7731BR Production24 ld SOIC - WideOTH 31-40 to 85C00N
AD7731BR-REEL7 Production24 ld SOIC - WideREEL 400-40 to 85C00N
AD7731BRU Production24 ld TSSOPOTH 62-40 to 85C00N
AD7731BRU-REEL7 Production24 ld TSSOPREEL 1000-40 to 85C00N
AD7731BRUZ Production24 ld TSSOPOTH 62-40 to 85C12.0910.28Y
AD7731BRUZ-REEL7 Production24 ld TSSOPREEL 1000-40 to 85C010.28Y
AD7731BRZ Production24 ld SOIC - WideOTH 31-40 to 85C12.6910.79Y
AD7731BRZ-REEL Production24 ld SOIC - WideREEL 1000-40 to 85C010.79Y
AD7731BRZ-REEL7 Production24 ld SOIC - WideREEL 400-40 to 85C010.79Y
Reference Materials
AD7731: Low Noise, High Throughput 24-Bit Sigma-Delta ADC Data Sheet (Rev. A) ad7731
AD7730/AD7730L/AD7731 Digital Filter Model ad7730
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-397: 标准线性集成电路的电诱发损坏 (Rev. 0) ad7715
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-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-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
MS-2210：高速ADC的电源设计 ad9861
Part 2: Circuit Suggestions Using Features and Functionality of New Sigma-Delta ad7715
Part 1: Circuit Suggestions Using Features and Functionality of New Sigma-Delta ad7715
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