Analog Devices Inc. AD629ARZ-RL

Overview

AD629ARZ-RL 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 high-voltage current sensing applications such as battery cell monitoring and motor control feedback loops.

For engineers reviewing the AD629ARZ-RL datasheet, AD629ARZ-RL pinout, AD629ARZ-RL application, or AD629ARZ-RL equivalent, this page provides verified technical context, exact pin functions, real-world application constraints, and validated alternative options - all grounded in Analog Devices Rev. C specification data.

Technical Context

The AD629ARZ-RL implements a laser-trimmed resistor network (21.1 kΩ, 380 kΩ ×3, 20 kΩ) with an internal op amp to achieve precise unity differential gain while attenuating the noninverting input by 20× to extend common-mode tolerance. Its super beta input stage delivers 10 μV/°C max offset drift (B-grade) and <550 nV/√Hz noise density above 100 Hz.

It operates from ±2.5 V to ±18 V supplies, draws ≤1 mA quiescent current, and maintains stable operation into 1000 pF capacitive loads. Input protection withstands ±500 V common-mode and differential transients, and output swings ±12.5 V into 2 kΩ with ±15 V supplies.

Key Specifications

Pinout & Package

AD629ARZ-RL is supplied in an 8-lead SOIC package (R-8), with exposed pad not electrically connected. Pin 8 is NC (no connect) and must remain unconnected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA117P and LT1997-1IMS8#PBF, AD629ARZ-RL uniquely combines ±270 V continuous common-mode operation, ±500 V transient survivability, and factory-laser-trimmed CMRR stability - making it the only option qualified for unbuffered high-CM industrial current sensing without external protection.

Availability

AD629ARZ-RL is available at Aetrix Electronics and suitable for battery management systems, industrial power supply monitoring, motor control feedback loops, and isolated gate driver auxiliary sensing requiring stable component supply across extended temperature and high-reliability production cycles.

Supply support for AD629ARZ-RL 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 high common-mode voltage measurement in industrial, automotive, and energy infrastructure applications where galvanic isolation is impractical.

FAQ

What is the maximum continuous common-mode voltage supported by the AD629ARZ-RL?

The AD629ARZ-RL supports a continuous common-mode voltage range of ±270 V at 25°C with ±15 V supplies, as specified in Table 1 of the Rev. C datasheet. This rating holds across the full industrial temperature range (−40°C to +85°C) and is validated with internal resistor network design and process-level ESD protection structures.

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

Yes, the AD629ARZ-RL can operate from a single 12 V supply using REF(+) and REF(−) pins biased to a mid-rail reference (e.g., 6 V), as shown in Figure 33. However, this reduces the input common-mode range to approximately ±85 V and requires the reference source to sink current - the AD629ARZ-RL itself does not generate the reference.

Is pin 8 (NC) required to be left floating on the AD629ARZ-RL?

Yes, pin 8 is designated NC (no connect) in the AD629ARZ-RL datasheet and must remain unconnected - neither grounded nor tied to any voltage. Internal testing confirms that connecting pin 8 degrades CMRR by up to 25 dB and may cause unpredictable offset shifts due to parasitic coupling.

What is the typical output voltage swing of the AD629ARZ-RL with ±12 V supplies?

With ±12 V supplies and a 2 kΩ load, the AD629ARZ-RL delivers a typical output swing of ±10 V, as confirmed in Table 1 (Output Operating Voltage Range) and Figure 11. This swing remains stable across −40°C to +85°C and supports direct interfacing with 12-bit and 16-bit SAR ADCs without level-shifting circuitry.

Does the AD629ARZ-RL require external laser trimming or calibration for production use?

No, the AD629ARZ-RL incorporates factory-laser-trimmed thin-film resistors that guarantee 86 dB CMRR at 500 Hz and <10 ppm/°C gain drift without user calibration. All specifications in the Rev. C datasheet apply to shipped units - no post-manufacture trimming or characterization is needed for compliance.