Analog Devices Inc. AD8228BRZ-R7

Overview

AD8228BRZ-R7 from Analog Devices is a precision instrumentation amplifier with 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–60 Hz. It operates on dual supplies from ±2.3 V to ±18 V and is used in high-accuracy bridge signal conditioning for industrial weigh scales and strain gage interfaces.

For engineers reviewing the AD8228BRZ-R7 datasheet, AD8228BRZ-R7 pinout, AD8228BRZ-R7 application, or AD8228BRZ-R7 equivalent, this page delivers verified specifications, package mapping, gain configuration logic, real-world use constraints (e.g., REF pin impedance <1 Ω), and validated alternatives for precision analog signal chains requiring low drift and high CMRR.

Technical Context

The AD8228BRZ-R7 uses a three-op-amp architecture with internal laser-trimmed resistors to achieve 0.02% gain error (G=10, B grade) and 2 ppm/°C gain drift - eliminating external resistor matching dependencies. Its input stage employs matched bipolar transistors with diode-drop biasing to replicate differential input voltage across precision R3/R4 networks.

Gain selection is hardware-defined: open G1/G2 pins yield G=10; shorted G1/G2 pins yield G=100. The reference terminal (REF) sets output common-mode level, but source impedance >1 Ω degrades CMRR due to asymmetric amplification of the positive input path.

Key Specifications

Pinout & Package

AD8228BRZ-R7 is housed in an 8-lead SOIC package (body width 3.9 mm, JEDEC MS-012). Pin functions are electrically validated per Analog Devices Rev. 0 datasheet Figure 2 and Table 6.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD8221ARZ and INA128UA, AD8228BRZ-R7 offers the lowest gain drift (2 ppm/°C) and highest guaranteed CMRR stability over temperature - making it optimal for metrology-grade bridge signal chains where recalibration intervals must exceed 12 months.

Availability

AD8228BRZ-R7 is available at Aetrix Electronics and suitable for industrial weigh scales, precision data acquisition systems, and medical instrumentation requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for AD8228BRZ-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, headquartered in Wilmington, MA, with design centers worldwide.

The AD8228 belongs to Analog Devices' precision instrumentation amplifier product line, engineered specifically for low-drift, high-CMRR signal conditioning in bridge-based sensor interfaces where dc accuracy and thermal stability are paramount.

FAQ

What gain options does the AD8228BRZ-R7 support, and how are they configured?

The AD8228BRZ-R7 supports two fixed gains: 10 and 100. Gain is selected solely by the state of pins G1 (pin 2) and G2 (pin 3): leave both pins unconnected for G=10; short them together for G=100. No external resistors or control signals are required. This hardware-select method ensures repeatable, drift-free gain without layout-dependent matching errors - a key advantage of the AD8228BRZ-R7 over resistor-set alternatives.

Can the AD8228BRZ-R7 operate from a single supply?

Yes, the AD8228BRZ-R7 operates on single or dual supplies within ±2.3 V to ±18 V. For single-supply use, connect −VS to ground and apply VCC to +VS. Input common-mode range extends from −VS+1.9 V to +VS−1.2 V, so with +VS = 5 V and −VS = 0 V, inputs must stay within 1.9 V to 3.8 V. Output swing is similarly rail-limited. The REF pin allows level-shifting the output to match ADC reference points - essential for single-supply data acquisition systems using the AD8228BRZ-R7.

What is the maximum allowable source impedance on the REF pin of the AD8228BRZ-R7?

The AD8228BRZ-R7 REF pin must be driven with source impedance <1 Ω to maintain specified CMRR. Higher impedance introduces unequal gain in the positive input path due to interaction with the internal 10 kΩ resistor network, degrading CMRR by up to 20 dB. If a buffered voltage reference is used, ensure its output impedance is ≤1 Ω at DC and low frequencies. For passive level-shifting, use a low-impedance divider with ≤100 Ω total resistance - verified in AD8228BRZ-R7 layout guidelines and Figure 43 of the datasheet.

How does the AD8228BRZ-R7 handle input overvoltage conditions?

The AD8228BRZ-R7 input structure withstands continuous dc overvoltage up to ~3.5 V beyond either supply rail. For larger transients (e.g., ESD or defibrillator pulses), external protection is required: series current-limiting resistors (≥600 Ω per input for 6 mA max) plus low-leakage clamping diodes (e.g., BAV199L). The absolute maximum rating is ±18 V on any pin. These limits are defined in AD8228BRZ-R7 Absolute Maximum Ratings Table 4 and confirmed in the Input Protection section of the datasheet.

Is the AD8228BRZ-R7 suitable for driving SAR ADCs directly?

Yes, the AD8228BRZ-R7 can directly drive medium-speed SAR ADCs (e.g., 1 MSPS, 16-bit) when output load ≤10 kΩ. Its 2 V/μs slew rate and 650 kHz bandwidth (G=10) support settling to 0.01% in 6 μs - sufficient for 100 kSPS sampling. For faster ADCs or capacitive loads >100 pF, add a small series resistor (10–50 Ω) between VOUT and ADC input to isolate capacitance and prevent peaking. This behavior is documented in AD8228BRZ-R7 Figure 37–38 (small-signal response) and confirmed in Applications Information section.