Analog Devices Inc. AD629BRZ-R7

Overview

AD629BRZ-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 non-galvanically isolated current sensing applications such as battery cell monitoring and motor control feedback loops.

For engineers reviewing the AD629BRZ-R7 datasheet, AD629BRZ-R7 pinout, AD629BRZ-R7 application, or AD629BRZ-R7 equivalent, this page provides verified specifications, functional pin mapping, real-world use cases, and validated alternative options - all confirmed against Analog Devices Rev. C datasheet and SOIC-8 packaging documentation.

Technical Context

The AD629BRZ-R7 integrates a laser-trimmed resistor network with a super-beta op amp to achieve precise differential gain of 1 while rejecting common-mode signals up to ±270 V. Its internal 20:1 attenuation on the noninverting path (via REF(+) and REF(−)) enables wide-range common-mode operation without external components.

It features low drift performance: 10 μV/°C max offset drift (B-grade), 10 ppm/°C max gain drift, and maintains ≥73 dB CMRR across −40°C to +85°C. Input protection extends to ±500 V common-mode and differential transients, supporting robust operation in industrial power systems.

Key Specifications

Pinout & Package

AD629BRZ-R7 is packaged in an 8-lead SOIC (Small Outline Integrated Circuit) with standard JEDEC MS-012AC footprint, 1.27 mm pitch, and RoHS-compliant lead finish. The package supports surface-mount reflow and is rated for industrial temperature operation (−40°C to +85°C).

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA117P and LT6372-1, AD629BRZ-R7 uniquely combines ±270 V common-mode tolerance, ±500 V transient protection, and industrial-grade drift specs - making it the only drop-in solution for ruggedized HV current sensing where isolation is unnecessary but reliability is critical.

Availability

AD629BRZ-R7 is available at Aetrix Electronics and suitable for battery management systems, industrial motor controls, and high-voltage power supply monitoring requiring stable component supply, long-term lifecycle assurance, and guaranteed industrial temperature performance.

Supply support for AD629BRZ-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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The AD629 belongs to Analog Devices' precision difference amplifier product line, designed specifically for accurate high common-mode voltage measurement in industrial, automotive, and energy infrastructure applications without galvanic isolation.

FAQ

What is the maximum common-mode voltage the AD629BRZ-R7 can handle continuously?

The AD629BRZ-R7 supports continuous operation at ±270 V common-mode voltage per the Rev. C datasheet. Absolute maximum ratings allow ±300 V continuous and ±500 V for 10 seconds - but sustained operation above ±270 V risks specification compliance and long-term reliability. Designers should maintain margin below ±270 V for robust industrial deployment of AD629BRZ-R7.

Does AD629BRZ-R7 require external resistors to set gain?

No. AD629BRZ-R7 has a fixed unity gain (1 V/V) achieved via internal laser-trimmed resistors. No external gain-setting components are needed - unlike general-purpose op amps or instrumentation amplifiers. This eliminates resistor matching errors and reduces PCB area, making AD629BRZ-R7 ideal for space-constrained HV sensing layouts.

Can AD629BRZ-R7 operate from a single supply?

Yes. AD629BRZ-R7 supports single-supply operation by biasing REF(+) and REF(−) to a stable mid-rail reference voltage (e.g., 2.5 V or 5 V). Output then swings symmetrically around that reference. However, common-mode input range shrinks - for example, with 10 V supply and 5 V reference, usable CM range becomes +85 V to –75 V, as specified in the Rev. C datasheet.

What is the purpose of the NC pin (Pin 8) on AD629BRZ-R7?

Pin 8 is designated NC (No Connect) and is internally unconnected. It must remain electrically floating - no trace, solder, or grounding is permitted. Connecting Pin 8 may degrade CMRR, increase noise, or cause latch-up. The AD629BRZ-R7 datasheet explicitly states "Do not connect to this pin," and layout guidelines require keeping this pad isolated in Gerber files.

How does AD629BRZ-R7 compare to isolation amplifiers in high-voltage applications?

AD629BRZ-R7 replaces costly isolation amplifiers in applications where galvanic isolation is unnecessary but high common-mode rejection is essential. Unlike isolation amplifiers, AD629BRZ-R7 uses no transformers or capacitors for signal coupling - delivering lower propagation delay (<15 µs), higher bandwidth (500 kHz), and better DC accuracy. It is not a safety-isolated device and must be used within reinforced insulation boundaries per IEC 61000-4-5.