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Analog Devices Inc. AD7731BR-REEL
- Part No.:
- AD7731BR-REEL
- Manufacturer:
- Analog Devices Inc.
- Category:
- Analog to Digital Converters (ADC)
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
AD7731BR-REEL.pdf
- Description:
- IC ADC 24BIT SIGMA-DELTA 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,450
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Product details
Overview
AD7731BR-REEL from Analog Devices is a 24-bit sigma-delta analog-to-digital converter optimized for high-precision process control front ends. It integrates a programmable-gain amplifier (PGA), buffered differential inputs, a 22-tap FIR + SINC³ digital filter, and self/system calibration logic. With 16-bit peak-to-peak resolution at 800 Hz, ±20 mV to ±1.28 V bipolar input ranges, and <5 nV/°C offset drift, it directly digitizes low-level transducer outputs in industrial PLCs and instrumentation.
For engineers reviewing the AD7731BR-REEL datasheet, AD7731BR-REEL pinout, AD7731BR-REEL application, or AD7731BR-REEL equivalent, this page delivers verified technical context, real-world timing and noise performance, FASTStep™ channel sequencing behavior, calibrated gain drift (<2 ppm/°C), and SOIC_W package–specific layout guidance - all grounded in Analog Devices' Rev. A specification and functional block diagram.
Technical Context
The AD7731BR-REEL implements a two-stage digital filter: a programmable SINC³ modulator output stage followed by a selectable 22-tap FIR or FASTStep™ adaptive filter. Its chopper-stabilized PGA supports six differential or five pseudo-differential input configurations with gain settings enabling direct connection to strain gauges and RTDs.
It features dual calibration modes (self and system), a dedicated SYNC pin for multi-device synchronization, and configurable serial interface polarity (POL) supporting both rising- and falling-edge SCLK protocols. The device operates from a single +5 V AVDD and +2.7 V to +5.25 V DVDD, with standby current as low as 10 µA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Resolution | 24-bit no-missing-codes architecture ensures monotonic conversion across full scale. |
| Peak-to-Peak Resolution | 16 bits at 800 Hz output rate - sufficient for 0.0015% nonlinearity-critical weight scales and pressure sensors. |
| Input Ranges | Seven unipolar (0 to +1.28 V) and seven bipolar (±1.28 V) ranges - selectable via RN2–RN0 bits for direct transducer interfacing. |
| Offset Drift | <5 nV/°C (CHP = 1 mode) - enables stable zero-point accuracy over –40°C to +85°C industrial temperature range. |
| Gain Drift | 2 ppm/°C max - eliminates recalibration needs in fixed-gain sensor signal chains. |
| Common-Mode Rejection | 110 dB on AIN at 20 mV range - rejects noise from shared ground paths in noisy factory environments. |
| Power Supply Rejection | 110 dB at 20 mV input - maintains accuracy despite ripple on +5 V AVDD rail. |
Pinout & Package
The AD7731BR-REEL is housed in a 24-lead SOIC_W (RW-24) package with 0.3 inch body width and standard JEDEC MS-013 footprint. Pin 1 is located at top-left corner when notch faces upward; pin numbering proceeds counterclockwise.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SCLK | Serial clock input | Schmitt-triggered; determines data transfer timing for SPI-compatible reads/writes - idle state depends on POL setting. |
| MCLK IN / MCLK OUT | Master clock interface | Accepts 1–5 MHz crystal/resonator or external CMOS clock; MCLK OUT provides inverted clock for synchronous peripherals. |
| AIN1–AIN6 | Programmable analog inputs | Three fully differential pairs or five pseudo-differential channels; AIN3/D1 and AIN4/D0 are reconfigurable as digital I/O. |
| REF IN(+), REF IN(–) | Differential reference inputs | Support +2.5 V (HIREF = 0) or +5 V (HIREF = 1) ratiometric references; 120 dB rejection on REF IN path. |
| SYNC | Multi-device synchronization | Resets digital filters and analog modulators simultaneously - essential for synchronized sampling across multiple AD7731BR-REEL units. |
| STANDBY | Low-power mode control | Pulling low reduces total supply current to ~10 µA - enables rapid wake-up without full reinitialization. |
Key Features
| Feature | Design Value |
|---|---|
| FASTStep™ adaptive filtering | Switches second-stage FIR to fast-settling filter upon step input detection - achieves 13-bit settling in 1 ms for multiplexed channel scanning. |
| Transducer burnout detection | Integrated ±100 nA current sources on AIN1(+) and AIN1(–) - enables open-wire fault detection without external components. |
| Buffered high-impedance inputs | On-chip buffer presents >1 GΩ input impedance - allows direct connection to high-Z sensors (e.g., thermocouples, piezoresistive elements) without loading error. |
| Self and system calibration | Internal zero- and full-scale calibration reduces offset to ~3 µV and gain error to <100 ppm - eliminates manual trim potentiometers. |
| Chopper-stabilized PGA | Removes 1/f noise and drift in signal path - delivers <0.5 µV/°C offset drift in CHP = 0 mode for ultra-stable DC measurements. |
Applications
| PLC Analog Input Module | High-Accuracy Weigh Scale |
|---|---|
|
Use Scenario: Digitizing 4–20 mA loop signals and millivolt-level load cell outputs in modular industrial controllers. IC Role / Device Role / Timing Role: Primary ADC front end with integrated PGA, reference buffer, and digital filtering - replaces discrete op-amp, filter, and calibration circuitry. Use Value: Achieves 16-bit p-p resolution at 800 Hz while supporting 1 ms inter-channel settling - enables simultaneous acquisition of 6 sensor channels per update cycle. |
Use Scenario: Converting microvolt-level bridge outputs from precision weighing platforms with temperature compensation. IC Role / Device Role / Timing Role: High-linearity, low-drift sigma-delta converter with built-in burnout detection and ratiometric reference support. Use Value: Delivers <15 ppm integral nonlinearity and <5 nV/°C offset drift - meets OIML R76 Class III requirements without external trimming. |
| Process Transmitter | RTD Temperature Transmitter |
|
Use Scenario: Converting thermocouple or 4–20 mA field signals into digital data for HART-enabled smart transmitters. IC Role / Device Role / Timing Role: Standalone analog front end with self-calibration, serial interface, and low-power standby - interfaces directly to microcontroller UART/SPI. Use Value: Supports unipolar 0–1.28 V and bipolar ±1.28 V ranges - accommodates wide dynamic range of industrial sensors while maintaining 24-bit code density. |
Use Scenario: Measuring Pt100/1000 RTD resistance changes using constant-current excitation and ratiometric voltage measurement. IC Role / Device Role / Timing Role: Precision ADC with differential reference input and programmable gain - enables 0.1°C resolution over –200°C to +850°C range. Use Value: 110 dB common-mode rejection at low input ranges suppresses lead-wire noise - critical for 3-wire/4-wire RTD configurations in EMI-heavy plants. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-resolution sigma-delta ADC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AD7791BRUZ | 24-bit, 16.6 Hz max output rate; lower power (400 µA); no FASTStep™ or burnout current sources. | Better suited for battery-powered portable instruments than high-throughput PLC modules. | Select AD7791BRUZ only if update rate ≤16.6 Hz suffices and board space/power budget constrain use of AD7731BR-REEL. |
| ADS1258IPWR | 24-bit, 125 kSPS; higher speed but higher noise floor (150 nVRMS); no integrated PGA or burnout detection. | Targets high-speed data acquisition, not low-drift process control - requires external signal conditioning. | Choose ADS1258IPWR only when throughput >1 kHz is mandatory and system-level calibration can compensate for missing on-chip features. |
Compared with AD7791BRUZ and ADS1258IPWR, the AD7731BR-REEL uniquely combines 800 Hz throughput, on-chip burnout detection, FASTStep™ multiplexing, and <5 nV/°C drift - making it the only option that satisfies full-spectrum requirements of industrial analog input modules without external support circuitry.
Availability
AD7731BR-REEL is available at Aetrix Electronics and suitable for industrial PLCs, high-accuracy weigh scales, and process transmitter designs requiring stable component supply, long-term lifecycle continuity, and RoHS-compliant sourcing.
Supply support for AD7731BR-REEL includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets since 1965.
The AD7731BR-REEL belongs to Analog Devices' precision sigma-delta ADC product line, engineered specifically for ruggedized process control and instrumentation where low drift, high CMRR, and integrated transducer interface functionality are mandatory.
FAQ
What is the maximum output data rate supported by the AD7731BR-REEL?
The AD7731BR-REEL supports programmable output rates up to 6.4 kHz in SKIP mode, where only the SINC³ filter is active. In normal mode with both SINC³ and 22-tap FIR filtering enabled, the maximum rate is 800 Hz - delivering 16-bit peak-to-peak resolution. The device's FASTStep™ mode maintains 13-bit resolution during 1 ms channel switching, making it ideal for multiplexed sensor arrays.
Does the AD7731BR-REEL require an external reference voltage?
No, the AD7731BR-REEL accepts a differential reference input (REF IN(+) and REF IN(–)) and supports nominal +2.5 V or +5 V references depending on the HIREF bit setting. It does not include an internal reference; however, its 120 dB reference input common-mode rejection and built-in NO REF fault detection simplify robust ratiometric designs using external precision references like the ADR441.
Can the AD7731BR-REEL interface directly with a microcontroller SPI bus?
Yes, the AD7731BR-REEL features an SPI-compatible three-wire serial interface (SCLK, DIN, DOUT) with CS and POL pins enabling seamless integration with most microcontrollers. Its Schmitt-triggered SCLK input tolerates slow edges, and POL selection allows matching to either rising- or falling-edge clock protocols - eliminating level-shifting or timing glue logic in typical ARM Cortex-M or PIC-based systems.
How does the FASTStep™ mode improve channel switching performance in the AD7731BR-REEL?
FASTStep™ mode dynamically replaces the default 22-tap FIR filter with a faster-settling adaptive filter upon detecting a step change at the input. This reduces settling time from ~100 ms to 1 ms while preserving 13-bit peak-to-peak resolution - enabling rapid scanning across up to six analog inputs without sacrificing accuracy. The feature is enabled via the FASTSTEP bit in the Mode Register and requires no host intervention once configured.
What package type is used for the AD7731BR-REEL, and is it compatible with standard SOIC footprints?
The AD7731BR-REEL uses a 24-lead SOIC_W (wide-body) package (RW-24), measuring 7.5 mm × 15.4 mm with 0.3 inch body width and 0.635 mm pitch. It is mechanically and solder-reflow compatible with industry-standard SOIC-24 footprints per JEDEC MS-013, including thermal pad variants - no PCB redesign is needed when upgrading from legacy SOIC-24 ADCs.
AD7731BR-REEL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Number of Bits:
- 24
- Sampling Rate (Per Second):
- 6.4k
- Number of Inputs:
- 3, 5
- Input Type:
- Differential
- Data Interface:
- SPI, DSP
- Configuration:
- MUX-PGA-ADC
- Ratio - S/H:ADC:
- -
- Number of A/D Converters:
- 1
- Architecture:
- Sigma-Delta
- Reference Type:
- External
- Voltage - Supply, Analog:
- 5V
- Voltage - Supply, Digital:
- 5V
- Features:
- PGA
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 24-SOIC
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
AD7731BR-REEL FAQ
1.How can I place an order for AD7731BR-REEL through Aetrix?
Please submit a Request for Quotation (RFQ) for AD7731BR-REEL on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for AD7731BR-REEL reliable?
The price and inventory of AD7731BR-REEL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7731BR-REEL is usually 5 days.
3.What payment methods are accepted for AD7731BR-REEL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7731BR-REEL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD7731BR-REEL?
AD7731BR-REEL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD7731BR-REEL order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for AD7731BR-REEL?
For technical support, including AD7731BR-REEL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7731BR-REEL requirements.
6.How does Aetrix verify that AD7731BR-REEL is sourced from the original manufacturer or authorized distributors?
All AD7731BR-REEL products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that AD7731BR-REEL meets industry standards.
7.What is the process for return or replacement of AD7731BR-REEL?
All AD7731BR-REEL units undergo pre-shipment inspection (PSI). If there is an issue with AD7731BR-REEL, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The AD7731BR-REEL part is unused and in its original packaging.
Return procedure for AD7731BR-REEL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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