Analog Devices Inc. AD8422BRZ-R7

Overview

AD8422BRZ-R7 from Analog Devices is a high-precision, low-power, rail-to-rail instrumentation amplifier optimized for bridge sensor signal conditioning. It delivers 150 dB CMRR at G = 1000, 0.04% max gain error, 0.3 µV/°C input offset drift, and 368 µA quiescent current - enabling high-channel-count precision data acquisition in medical and industrial systems.

For engineers reviewing the AD8422BRZ-R7 datasheet, AD8422BRZ-R7 pinout, AD8422BRZ-R7 application, or AD8422BRZ-R7 equivalent, key selection criteria include guaranteed −40°C to +85°C performance, 8-lead SOIC_N package compatibility, input overvoltage protection (±40 V from opposite supply), and single-resistor programmable gain from 1 to 1000.

Technical Context

The AD8422BRZ-R7 implements a laser-trimmed, 3-op-amp instrumentation topology with superbeta input transistors, achieving ultralow input bias current (0.5 nA max) and 8 nV/√Hz input voltage noise at 1 kHz. Its architecture replicates differential input voltage across the external RG resistor to set gain, preserving common-mode rejection across frequency and temperature.

It supports dual-supply (±2.3 V to ±18 V) or single-supply (4.6 V to 36 V) operation, features rail-to-rail output swing (within 200 mV of rails at RL = 10 kΩ), and includes robust input protection that maintains noise performance while tolerating continuous ±40 V input overvoltage relative to the opposite supply rail.

Key Specifications

Pinout & Package

The AD8422BRZ-R7 is housed in an 8-lead SOIC_N (Small Outline Integrated Circuit, Narrow) package with standard 1.27 mm pitch, compatible with automated PCB assembly and IPC-7351B footprint MS-012AA.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD8422BRZ-R7, AD8421ARMZ offers higher speed at the expense of precision and power efficiency, while INA828IDR reduces cost and current slightly but sacrifices CMRR and thermal stability - making AD8422BRZ-R7 optimal for metrology-grade, low-power, high-reliability measurement systems.

Availability

AD8422BRZ-R7 is available at Aetrix Electronics and suitable for medical instrumentation, industrial process controls, and precision data acquisition systems requiring stable component supply, long-term lifecycle support, and guaranteed −40°C to +85°C performance.

Supply support for AD8422BRZ-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 AD8422BRZ-R7 belongs to Analog Devices' precision instrumentation amplifier product line, engineered specifically for high-accuracy, low-power sensor signal conditioning in demanding DC-critical applications such as clinical diagnostics and factory automation.

FAQ

What is the maximum allowable input voltage beyond the supply rails for AD8422BRZ-R7?

The AD8422BRZ-R7 supports continuous input voltages up to ±40 V relative to the opposite supply rail - e.g., −IN and +IN can tolerate −VS − 40 V and +VS + 40 V respectively. This eliminates external protection circuitry in noisy industrial environments. The AD8422BRZ-R7 maintains full specified performance within this range without latch-up or parametric shift.

Does AD8422BRZ-R7 require external components to set gain, and what is the minimum RG value?

Yes, AD8422BRZ-R7 uses an external resistor across pins 2 and 3 (RG) to set gain per G = 1 + (19.8 kΩ/RG). The minimum allowed RG is 19.8 Ω, corresponding to G = 1001. For G = 1, leave RG pins open. Gain accuracy depends on RG tolerance and tempco; a 0.1% 25 ppm/°C resistor yields <0.11% total system gain error over temperature.

What is the operating temperature range for AD8422BRZ-R7, and how does performance change at extremes?

The AD8422BRZ-R7 is specified for −40°C to +85°C operation with guaranteed parameters including 150 dB CMRR at G = 1000 and 0.04% gain error. At −40°C, output swing degrades slightly (to −VS + 0.25 V), and quiescent current rises to 400 µA max. No derating is required below +85°C; extended operation to +125°C is possible but not fully characterized for all specs.

Can AD8422BRZ-R7 drive a 2 kΩ load while maintaining rail-to-rail output swing?

Yes, AD8422BRZ-R7 delivers rail-to-rail output swing into 2 kΩ loads: at ±15 V supplies, it swings to within 250 mV of each rail (−VS + 0.25 V to +VS − 0.25 V) at 25°C. At temperature extremes (−40°C to +85°C), swing is −VS + 0.3 V to +VS − 1.4 V due to current-limiting behavior at cold temperatures - verify against load requirements in worst-case conditions.

How does the REF pin function in AD8422BRZ-R7, and what are its voltage limits?

The REF pin sets the output common-mode voltage: VOUT = G × (VIN+ − VIN−) + VREF. It must be driven by a low-impedance source (<1 Ω) to avoid gain error. Voltage on REF must stay within ±0.3 V of either supply rail (i.e., −VS − 0.3 V ≤ VREF ≤ +VS + 0.3 V); exceeding this risks ESD diode conduction and output saturation. The AD8422BRZ-R7 uses REF to interface directly with unipolar ADC references.