Analog Devices Inc. AD8228BRMZ-R7

Overview

AD8228BRMZ-R7 from Analog Devices is a precision instrumentation amplifier optimized for high-accuracy bridge signal conditioning in industrial and medical systems. It delivers pin-strappable gains of 10 or 100, 2 ppm/°C gain drift (B grade), 50 μV max input offset voltage, and 100 dB CMRR at DC - enabling stable measurement of microvolt-level differential signals amid high common-mode interference.

For engineers reviewing the AD8228BRMZ-R7 datasheet, AD8228BRMZ-R7 pinout, AD8228BRMZ-R7 application, or AD8228BRMZ-R7 equivalent, this page provides verified specifications, validated pin functions, confirmed gain-setting behavior, real-world use cases in strain gage and transducer interfaces, and two rigorously cross-checked alternative parts with documented technical differences.

Technical Context

The AD8228BRMZ-R7 implements a laser-trimmed three-op-amp architecture with fully integrated, matched thin-film resistors - eliminating external gain-setting components and guaranteeing <2 ppm/°C gain drift and <0.02% gain error. Its input stage uses matched bipolar transistors with on-chip bias current compensation, delivering 0.6 nA max input bias current and 0.8 μV/°C max input offset drift.

It supports dual supplies from ±2.3 V to ±18 V and operates across −40°C to +125°C, with specified performance over −40°C to +85°C. Gain selection is implemented via physical shorting (G = 100) or open-circuit (G = 10) of Pins 2 and 3 - no configuration registers or digital interface required.

Key Specifications

Pinout & Package

AD8228BRMZ-R7 is housed in an 8-lead MSOP package (3 mm × 3 mm, 0.65 mm pitch), optimized for compact PCB layouts and thermal performance (θ_JA = 135°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD8228BRMZ-R7, AD8221ARMZ offers flexible gain at the expense of guaranteed low drift, while INA128UA trades precision and package size for broader availability and lower unit cost - making AD8228BRMZ-R7 the optimal choice when <2 ppm/°C drift and MSOP footprint are design-critical.

Availability

AD8228BRMZ-R7 is available at Aetrix Electronics and suitable for weigh scales, industrial process controls, and medical instrumentation requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across temperature.

Supply support for AD8228BRMZ-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.

The AD8228 belongs to Analog Devices' precision instrumentation amplifier product line, engineered specifically for demanding dc-critical applications including bridge-based sensors, strain gages, and medical transducers where gain stability and offset accuracy are non-negotiable.

FAQ

What gain options does the AD8228BRMZ-R7 support, and how are they configured?

The AD8228BRMZ-R7 supports two fixed gains: 10 and 100. Gain is selected solely by the state of Pins 2 (G1) and 3 (G2): leave both pins unconnected for G = 10; short them together for G = 100. No external resistors, jumpers, or digital configuration are required. This hardware-only method ensures repeatable, temperature-stable gain without layout-dependent parasitics - a key advantage of the AD8228BRMZ-R7 over programmable alternatives.

Does the AD8228BRMZ-R7 require external resistors for gain setting?

No, the AD8228BRMZ-R7 does not require external resistors for gain setting. All gain-setting resistors are internal, laser-trimmed thin-film elements fabricated on-die. This eliminates matching errors, thermal drift mismatches, and PCB layout sensitivity associated with external resistor networks - directly contributing to the AD8228BRMZ-R7's guaranteed 2 ppm/°C gain drift and 0.02% gain error.

What is the maximum common-mode input voltage range for the AD8228BRMZ-R7 at ±15 V supplies?

At ±15 V supplies, the AD8228BRMZ-R7 supports a common-mode input voltage range of −13.1 V to +13.8 V for G = 10 (Figure 11), and −13.2 V to +13.8 V for G = 100 (Figure 13). These limits arise from internal node headroom constraints in the three-op-amp architecture - not supply rail limitations - and are validated across −40°C to +85°C. Exceeding these ranges degrades CMRR and may cause clipping.

Can the AD8228BRMZ-R7 drive a 16-bit SAR ADC directly, and what REF pin considerations apply?

Yes, the AD8228BRMZ-R7 can directly drive a 16-bit SAR ADC when the REF pin is properly biased. The REF terminal sets the output common-mode level; for single-supply ADCs, tie REF to a clean, low-impedance midsupply voltage (e.g., V_DD/2). Source impedance to REF must be ≤1 Ω - higher impedance degrades CMRR due to unequal amplification of positive/negative paths. A dedicated low-noise buffer or precision resistor divider with bypass capacitor is recommended for ADC interfacing.

How does the AD8228BRMZ-R7 handle input overvoltage conditions beyond the supply rails?

The AD8228BRMZ-R7 tolerates continuous input voltages up to ±3.5 V beyond the supply rails due to internal ESD diode clamping. For sustained overvoltage (e.g., >6 mA input current), external series resistors are required: R_LIMIT ≥ (V_IN − V_SUPPLY) / 6 mA. At G = 100, differential inputs >5 V also trigger this limit. In defibrillator-grade applications, add low-leakage diodes (e.g., BAV199L) alongside series resistors - all validated in AD8228BRMZ-R7's absolute maximum ratings table.