Analog Devices Inc. AD7739BRU

Overview

AD7739BRU from Analog Devices is a 24-bit sigma-delta analog-to-digital converter (ADC) with eight single-ended or four fully differential input channels, ±0.0015% integral nonlinearity, 18-bit peak-to-peak resolution at 500 Hz, and 24-bit no-missing-codes performance - designed for high-precision industrial multiplexed data acquisition in PLCs and process control systems.

For engineers reviewing the AD7739BRU datasheet, AD7739BRU pinout, AD7739BRU application, or AD7739BRU equivalent, key selection considerations include its configurable 3-wire SPI-compatible serial interface, on-chip per-channel system calibration, 5 V analog / 3 V or 5 V digital supply operation, and extended industrial temperature range (–40°C to +105°C).

Technical Context

The AD7739BRU integrates a sigma-delta modulator with programmable filter word (FW) control, enabling conversion rates from 372 Hz to 15.1 kHz and supporting both chopping-enabled (low drift, ≤±25 nV/°C offset drift) and chopping-disabled (higher throughput) modes. Its analog front end accepts common-mode inputs from 200 mV above AGND to AVDD − 300 mV.

It features a differential reference input with no-reference detect capability, supports unipolar/bipolar input ranges of ±0.625 V, ±1.25 V, and ±2.5 V, and includes an internal buffer with 80–95 dB common-mode rejection at DC. The device uses a 24-lead TSSOP package with Schmitt-triggered logic inputs and dual ground separation (AGND/DGND).

Key Specifications

Pinout & Package

Package: 24-lead TSSOP (4.4 mm × 7.8 mm, 0.65 mm pitch), RoHS-compliant, thermal impedance θ_JA = 128°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7739BRU, AD7738BRU trades lower offset drift for higher throughput and external signal path access, while AD7734BRU sacrifices channel count and differential input capability to deliver extended input voltage range and overvoltage protection - making each optimal for distinct subsystem requirements.

Availability

AD7739BRU is available at Aetrix Electronics and suitable for PLC analog input modules, industrial weigh scales, process control transmitters, and energy metering front ends requiring stable component supply across extended temperature and long product lifecycles.

Supply support for AD7739BRU 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 AD7739BRU belongs to the AD773x family of high-precision, high-throughput sigma-delta ADCs engineered specifically for industrial process control, automation, and instrumentation where channel density, calibration autonomy, and noise immunity are critical.

FAQ

What is the maximum channel switching rate achievable with the AD7739BRU while maintaining 16-bit peak-to-peak resolution?

The AD7739BRU achieves 16-bit peak-to-peak resolution at a maximum channel switching rate of 4 kHz when chopping is disabled. This corresponds to a total conversion time of 250 µs per channel, verified under conditions of AVDD = 5 V, DVDD = 5 V, and MCLK = 6.144 MHz. At this rate, the device delivers true 16-bit p-p resolution with no missing codes and ±0.0015% INL after calibration. The AD7739BRU maintains this performance across its full –40°C to +105°C operating range.

Does the AD7739BRU support both unipolar and bipolar input configurations, and what are the supported voltage ranges?

Yes, the AD7739BRU supports both unipolar and bipolar input configurations across three nominal ranges: ±0.625 V, ±1.25 V, and ±2.5 V (bipolar), and 0–0.625 V, 0–1.25 V, and 0–2.5 V (unipolar). These ranges are selected via configuration registers and apply uniformly to all eight single-ended or four fully differential input channels. The analog input common-mode voltage must remain between 200 mV above AGND and AVDD − 300 mV, and the device tolerates absolute input voltages up to ±2.5 V in the ±2.5 V range mode.

How does the on-chip per-channel system calibration function in the AD7739BRU, and what errors does it correct?

The AD7739BRU's on-chip per-channel system calibration corrects offset and gain errors independently for each analog input channel using dedicated zero-scale and full-scale calibration registers. It reduces initial offset error from ±1 mV (chopping disabled) or ±10 µV (chopping enabled) to noise-limited levels, and gain error from ±0.2% to residual error matching the noise floor. Calibration is initiated via software command and completed in under 10 ms per channel, with results stored in nonvolatile shadow registers. This eliminates need for external calibration components or host MCU intervention during normal operation.

What is the role of the SYNC/P1 pin on the AD7739BRU, and how is it configured?

The SYNC/P1 pin on the AD7739BRU serves dual functions: as a system synchronization input to align the sigma-delta modulator and digital filter timing across multiple devices, or as a general-purpose I/O port (P1) controlled by the P1 DIR bit in the I/O port register. When used as SYNC, asserting a low pulse resets the modulator and filter phase, enabling coherent sampling in multi-ADC systems. As P1, it operates with analog-supply-referenced logic levels (0.8 V to 3.5 V for AVDD = 5 V) and supports 8 mA sink capability. Its direction and state are fully software-configurable without hardware changes.

Can the AD7739BRU operate with a 3 V digital supply while maintaining full specification performance?

Yes, the AD7739BRU fully supports DVDD = 3 V (2.7 V to 3.6 V) operation while meeting all AC/DC specifications, including 24-bit no missing codes, ±0.0015% INL, and 4 kHz channel switching at 16-bit p-p resolution. At 3 V DVDD, digital supply current drops to 1.0–1.5 mA (normal mode), power dissipation reduces to 50 mW (reduced power mode), and logic thresholds adjust to VINL = 0.4 V and VINH = 2.5 V. All timing parameters, interface compatibility (SPI/QSPI/MICROWIRE), and Schmitt trigger hysteresis remain guaranteed across the 3 V operating range.