Analog Devices Inc. AD7732BRU

Overview

AD7732BRU from Analog Devices is a 24-bit sigma-delta analog-to-digital converter with two fully differential input channels, ±10 V input range, 18-bit peak-to-peak resolution at 500 Hz, on-chip per-channel system calibration, and 3-wire SPI-compatible serial interface. It operates from a single 5 V analog supply and supports industrial process control instrumentation requiring high channel-switching throughput and overvoltage tolerance up to ±16.5 V.

For engineers reviewing the AD7732BRU datasheet, AD7732BRU pinout, AD7732BRU application, or AD7732BRU equivalent, key selection considerations include its 24-bit no-missing-codes performance, configurable chopping mode for noise vs. speed trade-off, dual-differential input architecture with independent channel calibration, and TSSOP-28 package compatibility with industrial temperature range (–40°C to +105°C).

Technical Context

The AD7732BRU implements a 24-bit sigma-delta ADC core with programmable filter word (FW) and chopping enable/disable control, enabling optimization between effective resolution (up to 21 bits effective at 500 Hz) and conversion rate (up to 15.4 kHz). Its analog front end integrates a low-drift multiplexer, input buffers tolerant to ±16.5 V common-mode overvoltage without adjacent channel crosstalk degradation, and internal reference detect circuitry.

It features dual independent channel setup registers, per-channel zero-scale and full-scale calibration registers, and a 3-wire serial interface with Schmitt-triggered logic inputs compatible with SPI, QSPI, MICROWIRE, and DSP controllers. The device supports both continuous and single-conversion modes with RDY output signaling data readiness.

Key Specifications

Pinout & Package

Package: 28-lead TSSOP (RoHS-compliant, 4.4 mm × 9.7 mm body, 0.65 mm pitch).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-resolution, multiplexed ADC applications.

Compared with AD7732BRU, AD7734BRU offers higher channel count at the expense of differential input integrity and overvoltage resilience, while AD7738BRU provides greater flexibility in channel configuration but mandates external front-end circuitry for ±10 V signals-making AD7732BRU optimal for dual-channel, high-fidelity, fault-tolerant industrial measurement.

Availability

AD7732BRU is available at Aetrix Electronics and suitable for PLC analog input modules, multiplexed sensor hubs, process controller ADC subsystems, high-accuracy weigh scales, and industrial data loggers requiring stable component supply across extended temperature and long product lifecycles.

Supply support for AD7732BRU 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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The AD7732BRU belongs to Analog Devices' precision sigma-delta ADC family designed specifically for industrial process control, PLCs, and high-accuracy instrumentation-emphasizing noise immunity, channel isolation, and robust operation in harsh electromagnetic environments.

FAQ

What is the maximum analog input voltage the AD7732BRU can tolerate without damage or performance degradation?

The AD7732BRU supports an absolute maximum AIN voltage of ±50 V per pin (per Absolute Maximum Ratings), but its specified overvoltage tolerance without affecting adjacent channel accuracy is ±16.5 V. At ±16.5 V, channel-to-channel isolation remains at 110 dB and INL stays within ±0.0015% FSR. Operation beyond ±16.5 V may trigger the OVR bit and require CLAMP bit configuration to manage data output behavior. The AD7732BRU maintains full functionality and specification compliance within this ±16.5 V range.

Does the AD7732BRU support true bipolar input ranges, and how is that implemented?

Yes, the AD7732BRU supports true bipolar input ranges including ±10 V and ±5 V on each fully differential input pair (AIN0, AIN1). This is achieved through internal programmable biasing and differential front-end architecture that references the input common-mode voltage to BIAS pins, allowing direct connection of bipolar transducers without external level-shifting circuitry. The device's analog input stage operates from a single 5 V AVDD supply while maintaining rail-to-rail common-mode handling from 0 V to AVDD – 300 mV, enabling seamless ±10 V acquisition.

How does the chopping mode affect the performance of the AD7732BRU, and when should it be enabled?

Chopping mode in the AD7732BRU reduces offset drift to ±2.5 µV/°C and improves low-frequency noise performance, making it ideal for slow-sampling, high-precision applications like weigh scales. When disabled, the AD7732BRU achieves faster conversion rates (up to 15.4 kHz) with slightly higher drift (±25 µV/°C) - better suited for dynamic measurements such as vibration monitoring. The choice is register-configurable and independent per channel, allowing mixed-mode operation in multi-sensor systems. Enabling chopping is recommended when temperature stability and sub-ppm offset accuracy outweigh raw speed requirements.

Can the AD7732BRU perform system calibration independently on each input channel?

Yes, the AD7732BRU supports per-channel system calibration via dedicated Channel Zero-Scale Calibration Registers and Channel Full-Scale Calibration Registers. Each channel (AIN0 and AIN1) has its own calibration coefficients stored in on-chip memory, allowing independent correction of gain and offset errors introduced by external signal conditioning or sensor nonlinearity. This capability eliminates inter-channel crosstalk in calibration and enables accurate multiplexed acquisition from mismatched sensor types-for example, calibrating a thermocouple input on AIN0 separately from a strain gauge bridge on AIN1-without recalibration overhead.

What serial interface protocols is the AD7732BRU compatible with, and what hardware signaling features ensure robust communication?

The AD7732BRU supports 3-wire SPI-compatible serial communication (SCLK, DIN, DOUT) with CS active-low control, and is explicitly compatible with SPI™, QSPI™, MICROWIRE™, and DSP serial interfaces. All digital inputs-including SCLK, CS, RESET, and SYNC/P1-feature Schmitt triggering with defined VT+ and VT– thresholds (e.g., 1.4 V/0.8 V at DVDD = 5 V), ensuring noise immunity against slow-rising edges and ground bounce. The RDY output provides hardware handshaking, and the interface operates reliably across DVDD voltages of 2.7–3.6 V or 4.75–5.25 V, making the AD7732BRU interoperable with diverse microcontrollers and real-time processors.