Analog Devices Inc. AD7711ARZ-REEL7

Overview

AD7711ARZ-REEL7 from Analog Devices is a 24-bit charge-balancing sigma-delta ADC with integrated programmable-gain amplifier (PGA), dual RTD excitation current sources (200 µA each), and on-chip 2.5 V reference. It supports differential and single-ended analog inputs, offers ±0.0015% integral nonlinearity, and operates from single or dual supplies (AVDD = 5–10 V, VSS = 0 or –5 V). It is designed for high-accuracy RTD-based temperature measurement in industrial process transmitters.

For engineers reviewing the AD7711ARZ-REEL7 datasheet, AD7711ARZ-REEL7 pinout, AD7711ARZ-REEL7 application, or AD7711ARZ-REEL7 equivalent, key selection considerations include its 24-bit no-missing-codes performance at ≤60 Hz filter notch, programmable gain (1–128), built-in RTD biasing, self/system/background calibration support, and SOIC-24 package compatibility with industrial PCB layouts.

Technical Context

The AD7711ARZ-REEL7 employs a charge-balancing sigma-delta modulator with on-chip digital filtering, where the first notch frequency is software-programmable via the 24-bit control register to set cutoff (e.g., 10 Hz, 50 Hz, 60 Hz) and settling time. Its analog front end includes a two-channel PGA with independent gain selection and polarity control, plus dedicated RTD1/RTD2 current outputs for 3-/4-wire configurations.

It features bidirectional serial interface (SCLK, SDATA, RFS, TFS, MODE, A0) supporting both self-clocking and external clocking modes, synchronous DRDY signaling, and full read/write access to calibration registers. The device uses separate analog (AGND) and digital (DGND) grounds, with VBIAS input enabling rail-to-rail common-mode range and PSRR up to 95 dB (gain-dependent).

Key Specifications

Pinout & Package

AD7711ARZ-REEL7 is housed in a 24-lead SOIC (R-24) package, 0.3-inch wide, RoHS-compliant, with gull-wing leads and standard JEDEC MS-013 footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7711ARZ-REEL7, AD7714BRUZ offers more channels but adds design complexity for RTD biasing, while ADS1248IPWR reduces board area and power but trades off reference integration and linearity - making AD7711ARZ-REEL7 optimal for dedicated, high-accuracy RTD transmitter designs requiring minimal external components.

Availability

AD7711ARZ-REEL7 is available at Aetrix Electronics and suitable for RTD transducer interfaces, smart industrial transmitters, and portable measurement instruments requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for AD7711ARZ-REEL7 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 AD7711ARZ-REEL7 belongs to Analog Devices' precision sigma-delta ADC product line, engineered specifically for high-resolution, low-noise, low-frequency measurement systems such as RTD-based temperature instrumentation and process control signal conditioning.

FAQ

What is the maximum sampling rate of the AD7711ARZ-REEL7?

The AD7711ARZ-REEL7 sampling rate is determined by the master clock (MCLK IN) divided by 256: f_S = f_{MCLK IN}/256. With a 10 MHz clock, the maximum rate is 39.06 kSPS; however, usable output data rate depends on filter configuration - e.g., 16.7 Hz at 10 Hz notch, 50 Hz at 50 Hz notch. The AD7711ARZ-REEL7 is optimized for low-speed, high-accuracy applications, not high-throughput sampling.

Does the AD7711ARZ-REEL7 support both unipolar and bipolar input ranges?

Yes, the AD7711ARZ-REEL7 supports both ranges via the B/U bit in the control register. Unipolar mode (B/U = 1) yields 0 to +V_REF/GAIN input range; bipolar mode (B/U = 0) yields ±V_REF/GAIN. Output coding is natural binary for unipolar and offset binary for bipolar. This flexibility allows the AD7711ARZ-REEL7 to interface with both grounded and floating sensor configurations.

Can the AD7711ARZ-REEL7 operate from a single 5 V supply?

Yes, the AD7711ARZ-REEL7 supports single-supply operation: tie VSS to AGND, set AVDD = 5 V ±5%, and DVDD = 5 V. Input signals must remain > –30 mV relative to VSS (i.e., > –30 mV vs AGND). For negative input capability, VSS must be driven negative (e.g., –5 V), enabling inputs down to –V_REF. The AD7711ARZ-REEL7's dual-supply flexibility simplifies design across varied industrial power architectures.

How does the AD7711ARZ-REEL7 handle RTD lead resistance in 3-wire configurations?

The AD7711ARZ-REEL7 uses RTD2 to inject matching 200 µA current into the sense lead, enabling cancellation of lead resistance voltage drop in software or firmware. When RTD1 excites the main RTD element and RTD2 biases the return lead, the differential measurement at AIN1(+) and AIN1(–) inherently rejects lead resistance error - a key advantage that eliminates external compensation circuitry and makes the AD7711ARZ-REEL7 ideal for precision 3-wire RTD systems.

Is the internal 2.5 V reference of the AD7711ARZ-REEL7 suitable as an external system reference?

Yes, the AD7711ARZ-REEL7's REF OUT pin provides a buffered 2.5 V ±1% (25°C), 20 ppm/°C drift reference capable of sourcing up to 1 mA. It is explicitly designed for use as an external reference for other circuitry (e.g., DACs, comparators) or as the excitation source for the RTD itself. Using REF OUT ensures ratiometric accuracy and eliminates mismatch between reference and excitation - a critical benefit realized directly in the AD7711ARZ-REEL7's architecture.