Features and Benefits
- Low power:
330 μA maximum quiescent current
- Low noise and distortion
8 nV/√Hz maximum input voltage noise at 1 kHz
0.15 μV p-p RTI noise (G = 100)
0.5 ppm nonlinearity with 2 kΩ load (G = 1)
- Excellent ac specifications
80 dB minimum CMRR at 10 kHz (G = 1)
2.2 MHz bandwidth (G = 1)
- High precision dc performance (AD8422BRZ)
150 dB minimum CMRR (G = 1000)
0.04% maximum gain error (G = 1000)
0.3 μV/°C maximum input offset drift
0.5 nA maximum input bias current
- Wide supply range
4.6 V to 36 V single supply
±2.3 V to ±18 V dual supply
Input overvoltage protection:
- 40 V from opposite supply
Gain range: 1 to 1000
The AD8422 is a high precision, low power, low noise, rail-to-rail instrumentation amplifier that delivers the best performance per unit microampere in the industry. The AD8422 processes signals with ultralow distortion performance that is load independent over its full output range.
The AD8422 is the third generation development of the industry standard AD620. The AD8422 employs new process technologies and design techniques to achieve higher dynamic range and lower errors than its predecessors, while consuming less than one-third of the power. The AD8422 uses the high performance pinout introduced by the AD8221.
Very low bias current makes the AD8422 error-free with high source impedance, allowing multiple sensors to be multiplexed to the inputs. Low voltage noise and low current noise make the AD8422 an ideal choice for measuring a Wheatstone bridge.
The wide input range and rail-to-rail output of the AD8422 bring all of the benefits of a high performance in-amp to singlesupply applications. Whether using high or low supply voltages, the power savings make the AD8422 an excellent choice for high channel count or power sensitive applications on a very tight error budget.
The AD8422 uses robust input protection that ensures reliability without sacrificing noise performance. The AD8422 has high ESD immunity, and the inputs are protected from continuous voltages up to 40 V from the opposite supply rail.
A single resistor sets the gain from 1 to 1000. The reference pin can be used to apply a precise offset to the output voltage. The AD8422 is specified from −40°C to +85°C and has typical performance curves to 125°C. It is available in 8-lead MSOP and 8-lead SOIC packages.
- Medical instrumentation
- Industrial process controls
- Strain gages
- Transducer interfaces
- Precision data acquisition systems
- Channel-isolated systems
- Portable instrumentation
Markets & Technology
- In Vitro Diagnostics
- Temperature Measurement
- Insulin Pump
- Vital Signs Measurements
- Electrocardiogram (ECG) Measurement
- Electroencephalogram (EEG) Measurement
- Respiration Rate Measurement
- Disease Management & Wellness
- Body Composition, Hydration, Bioimpedance Analysis
- Life Sciences & Medical Instrumentation
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (1)
Analog Devices provides a line of evaluation boards designed to help users evaluate our instrumentation amplifiers in 8 pin packages. Access the user guide UG-261.
This user guide describes three generic evaluation boards that can be used to evaluate many of Analog Devices instrumentation amplifiers. For information on the performance of a specific instrumentation amplifier, see the data sheet for that instrumentation amplifier.
- 3 generic, easy-to-use evaluation boards
- Shipped with an assortment of Analog Devices in-amps
- Solder in the in-amp to be tested
- Test pins already populated
- Decoupling capacitors already populated
- EVAL-INAMP-62RZ board: Compatible with AD620, AD621, AD622, AD623, AD627, AD8223, AD8225, LT1167, LT1168 and LT6370 in SOIC or PDIP
- EVAL-INAMP-82RZ board: Compatible with AD8221, AD8226, AD8227, AD8228, AD8229, AD8421, AD8428, and AD8429 in SOIC package
- EVAL-INAMP-82RMZ board: Compatible with AD8220, AD8221, AD8226, AD8227, AD8228, AD8236, and AD8421 in MSOP package
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
Models for the following parts are available in LTspice:
In-Amp Diamond Plot Tool
The Diamond Plot Tool is a web application that generates a configuration-specific Output Voltage Range vs. Input Common-Mode Voltage graph, also known as the Diamond Plot, for Analog Devices Instrumentation Amplifiers. Based on user inputs such as supply voltage, gain, and input signal range, the tool detects saturation and recommends in-amps for which the input signal is in-range and the configuration is valid. Avoid saturation, find the best in-amp for your design, and save time.
Technical Articles (1)
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.