Overview

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
* FASTStep is a trademark of Analog Devices, Inc.

Product Details

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

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Evaluation Kits (1)

Software & Systems Requirements

Tools & Simulations

Design Tools

Sigma-Delta ADC Tutorial

An interactive illustration showing the behavior of an idealized sigma-delta A/D converter.

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.

PCN-PDN Information

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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.


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