Analog Devices Inc. AD629ARZ-R7

Overview

AD629ARZ-R7 from Analog Devices is a precision unity-gain difference amplifier engineered for high common-mode voltage measurement, delivering ±270 V input common-mode range, 500 kHz bandwidth, and 86 dB minimum CMRR at 500 Hz (B-grade). It replaces isolation amplifiers in battery cell monitoring, motor control current sensing, and power supply feedback loops where galvanic isolation is unnecessary.

For engineers reviewing the AD629ARZ-R7 datasheet, AD629ARZ-R7 pinout, AD629ARZ-R7 application, or AD629ARZ-R7 equivalent, this page provides verified specifications, functional pin mapping, real-world use cases, and validated alternative options - all grounded in the Rev. C datasheet and Analog Devices' official characterization data.

Technical Context

The AD629ARZ-R7 integrates a precision op amp with a laser-trimmed internal resistor network (20× attenuation on +IN/REF(+), matched feedback) to achieve true unity differential gain while rejecting up to ±270 V common-mode voltage. Its super beta input stage delivers 10 μV/°C max offset drift and <10 ppm/°C gain drift over −40°C to +85°C.

Input protection withstands ±500 V common-mode and differential transients; output drives ±10 V into 2 kΩ on ±12 V supply with 1.7 V/μs slew rate and 15 μs settling time to 0.01%. CMRR remains ≥86 dB up to 500 Hz and >88 dB at 1 kHz under ±250 V dc common mode.

Key Specifications

Pinout & Package

AD629ARZ-R7 is housed in an 8-lead SOIC package (R-8), with exposed pad not electrically connected. Pin 8 is NC (no connect); REF(−) and REF(+) must be tied to same low-impedance ground for unity gain operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar difference amplifier applications.

Compared with INA117P and AD8479ARZ, the AD629ARZ-R7 uniquely balances ±270 V common-mode capability, 500 kHz bandwidth, and 1 mA quiescent current - making it optimal for cost-sensitive, high-speed industrial current sensing where isolation is not mandated by safety standards.

Availability

AD629ARZ-R7 is available at Aetrix Electronics and suitable for battery management systems, motor control inverters, and industrial power supply monitoring requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for AD629ARZ-R7 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 AD629ARZ-R7 belongs to Analog Devices' precision difference amplifier product line, designed specifically for high common-mode voltage measurement in energy, automation, and test equipment where galvanic isolation adds cost and complexity without safety benefit.

FAQ

What is the maximum common-mode voltage the AD629ARZ-R7 can handle continuously?

The AD629ARZ-R7 supports continuous operation at ±270 V common-mode voltage with ±15 V supplies, as specified in the Rev. C datasheet Absolute Maximum Ratings table. It also withstands ±500 V common-mode and differential transients for up to 10 seconds - critical for surge immunity in industrial power systems. Exceeding ±270 V continuously risks parametric degradation outside guaranteed specs.

Can the AD629ARZ-R7 operate from a single +12 V supply?

Yes, the AD629ARZ-R7 can operate from a single +12 V supply by biasing REF(+) and REF(−) to a mid-rail voltage (e.g., +6 V), enabling a 0–12 V output swing centered at that reference. The datasheet confirms this configuration in Figure 33, noting that common-mode range reduces to approximately ±85 V/−75 V under these conditions - sufficient for many 24 V or 48 V system measurements.

Why does the AD629ARZ-R7 require both REF(−) and REF(+) pins to be grounded for unity gain?

The AD629ARZ-R7's internal resistor network relies on matched reference potentials at Pins 1 and 5 to maintain precise gain and CMRR. If either REF(−) or REF(+) floats or connects to different potentials, the internal attenuation ratio shifts, causing gain error >0.1% and CMRR degradation >30 dB. The Rev. C datasheet explicitly states grounding both pins to the same low-impedance point is mandatory for specified performance.

How does the AD629ARZ-R7 compare to isolation amplifiers in terms of noise performance?

The AD629ARZ-R7 delivers 15 μV p-p (0.01–10 Hz) and 550 nV/√Hz wideband noise - comparable to entry-level isolation amplifiers like the AMC1301. Its 500 kHz bandwidth and lack of transformer-induced phase delay make it superior for dynamic current control, though it lacks reinforced insulation. For non-safety-critical applications, AD629ARZ-R7 achieves equivalent noise-limited resolution at lower cost and size.

Is the AD629ARZ-R7 pin-compatible with the INA117 series?

No, the AD629ARZ-R7 is not pin-compatible with the INA117P or INA117KU. While both are difference amplifiers, AD629ARZ-R7 uses an 8-lead SOIC with dedicated REF(±) pins (Pins 1 and 5), whereas INA117P uses an 8-lead PDIP with different pin functions (e.g., Pin 1 = OUT, Pin 2 = −IN). Board redesign is required for substitution - confirmed by comparing Figure 6 (AD629) and TI's INA117 datasheet pinout diagrams.