Analog Devices Inc. AD7709ARUZ-REEL7

Overview

AD7709ARUZ-REEL7 from Analog Devices is a 16-bit Σ-Δ analog-to-digital converter with integrated programmable gain amplifier (PGA), three switchable matched excitation current sources (200 µA, 200 µA, and 25 µA), low-side power switches, and a 4-bit digital I/O port. It supports fully differential or pseudo-differential input configurations across ±20 mV to ±2.56 V ranges, delivers 13-bit p-p resolution at 20 Hz on ±20 mV range, and enables simultaneous 50 Hz/60 Hz rejection in weigh-scale and RTD temperature measurement systems.

For engineers reviewing the AD7709ARUZ-REEL7 datasheet, AD7709ARUZ-REEL7 pinout, AD7709ARUZ-REEL7 application, or AD7709ARUZ-REEL7 equivalent, key selection criteria include its 24-lead TSSOP package, 3-wire SPI-compatible serial interface, single-supply operation (3 V or 5 V), rail-to-rail input buffer, and integrated V_BE-compatible current sources for 3-wire RTD sensing.

Technical Context

The AD7709ARUZ-REEL7 implements a Sinc³ digital filter with programmable decimation factor (SF = 13–255), enabling output update rates from 5.35 Hz to 105.03 Hz. Its Σ-Δ modulator operates at a fixed 32.768 kHz sampling rate derived from an on-chip PLL-driven crystal oscillator, and includes full-signal-chain chopping to suppress offset drift (±10 nV/°C typ) and enhance DC accuracy.

Input configuration flexibility includes two fully differential channels (AIN1/AIN2, AIN3/AIN4) or four pseudo-differential channels referenced to AINCOM. Reference selection supports dual independent inputs (REFIN1, REFIN2) with VREF Select™ for ratiometric or absolute measurements, while ISOURCE Select™ allows dynamic routing of excitation currents to IOUT1/IOUT2 terminals.

Key Specifications

Pinout & Package

AD7709ARUZ-REEL7 is housed in a 24-lead TSSOP (RU-24) package with exposed pad, rated for –40°C to +85°C operation. Pin functions are validated per Analog Devices' official AD7709 Rev. A datasheet (pp. 8–9).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision Σ-Δ ADC applications.

Compared with AD7709ARUZ-REEL7, AD7190BRUZ offers higher resolution but requires external excitation circuitry and GPIO, while ADS124S08IPW supports more channels but lacks integrated power switches and dual-reference flexibility - making AD7709ARUZ-REEL7 uniquely balanced for compact, self-contained sensor front ends.

Availability

AD7709ARUZ-REEL7 is available at Aetrix Electronics and suitable for pressure measurement, temperature sensing, and portable instrumentation requiring stable component supply, long-lifecycle availability, and RoHS-compliant packaging.

Supply support for AD7709ARUZ-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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The AD7709 belongs to Analog Devices' precision Σ-Δ ADC product line, designed specifically for low-frequency industrial and instrumentation applications requiring integrated signal conditioning, excitation, and digital interfacing in minimal footprint.

FAQ

What is the operating voltage range for AD7709ARUZ-REEL7?

The AD7709ARUZ-REEL7 operates from a single supply of 2.7 V to 3.6 V or 4.75 V to 5.25 V. It is specified for both 3 V and 5 V nominal operation, with typical power dissipation of 3.75 mW at 3 V. The device maintains full functionality across this range, including all gain settings, current source accuracy, and digital interface timing - making AD7709ARUZ-REEL7 suitable for mixed-voltage industrial systems and battery-backed instrumentation.

Does AD7709ARUZ-REEL7 support simultaneous 50 Hz and 60 Hz line-frequency rejection?

Yes, AD7709ARUZ-REEL7 achieves simultaneous 50 Hz and 60 Hz rejection using a 19.79 Hz update rate (SF = 72), delivering ≥100 dB normal-mode rejection at both frequencies. This capability is implemented in hardware via its Sinc³ filter architecture and does not require external notch filters or firmware-based digital subtraction - a key advantage of AD7709ARUZ-REEL7 in globally deployed sensor systems subject to variable mains frequencies.

How are the excitation current sources configured on AD7709ARUZ-REEL7?

The AD7709ARUZ-REEL7 integrates three switchable, ratioed current sources: IEXC1 and IEXC2 (200 µA each) and IEXC3 (25 µA). They are routed to IOUT1 and IOUT2 via on-chip switches controlled by configuration registers. Initial matching between IEXC1 and IEXC2 is ±2.5% (A grade), enabling precise 3-wire RTD compensation - a core functional differentiator of AD7709ARUZ-REEL7 versus generic Σ-Δ ADCs.

What package type and lead count does AD7709ARUZ-REEL7 use?

AD7709ARUZ-REEL7 uses a 24-lead TSSOP package (RU-24) with exposed thermal pad, measuring 7.8 mm × 4.4 mm × 1.2 mm. This RoHS-compliant, tape-and-reel packaged variant (REEL7 suffix) is optimized for automated SMT assembly and thermal performance in dense PCB layouts - consistent with the mechanical specifications defined in Analog Devices' AD7709 ordering guide.

Can AD7709ARUZ-REEL7 operate with an external clock instead of a crystal?

No, AD7709ARUZ-REEL7 requires a 32.768 kHz crystal connected between XTAL1 and XTAL2; it does not support external CMOS clock input. The on-chip oscillator inverter and PLL are designed exclusively for crystal resonance, and no alternative clocking mode is documented in the AD7709 datasheet. This design choice ensures low-jitter timing stability essential for the Sinc³ filter's notch placement - a defining characteristic of AD7709ARUZ-REEL7's noise-rejection performance.