1. Products
  2. Amplifiers
  3. Instrumentation Amplifiers
  4. AD621


Features and Benefits

  • Easy To Use
    Pin-Strappable Gains of 10 and 100
    All Errors Specified for Total System Performance
    High Performance than Discrete In Amp Designs
    Available in 8-Lead DIP and SOIC
    Low Power, 1.3 mA Max Supply Current
    Wide Power Supply
  • Low Noise
    9 nV/vHz, @ 1 kHz, Input Voltage Noise
    0.28 µV p-p Noise (0.1 Hz to 10 Hz)
  • Excellent DC Performance
    0.15% Max, Total Gain Error
    ±5 ppm/°C, Total Gain Drift
    125 µV Max, Total Offset Voltage
    1.0 µV/°C Max, Offset Voltage Drift
  • Excellent AC Specifications
    800 kHz Bandwidth (G = 10),
    200 kHz (G = 100)
    12 µs Settling Time to 0.01%

Product Details

The AD621 is an easy to use, low cost, low power, high accuracy instrumentation amplifier which is ideally suited for a wide range of applications. Its unique combination of high performance, small size and low power, outperforms discrete in amp implementations. High functionality, low gain errors and low gain drift errors are achieved by the use of internal gain setting resistors. Fixed gains of 10 and 100 can be easily set via external pin strapping. The AD621 is fully specified as a total system, therefore, simplifying the design process.

For portable or remote applications, where power dissipation, size and weight are critical, the AD621 features a very low supply current of 1.3 mA max and is packaged in a compact 8-pin SOIC, 8-pin plastic DIP or 8-pin cerdip. The AD621 also excels in applications requiring high total accuracy, such as precision data acquisition systems used in weigh scales and transducer interface circuits. Low maximum error specifications including nonlinearity of 10 ppm, gain drift of 5 ppm°/C, 50 µV offset voltage and 0.6 mV/°C offset drift ("B" grade), make possible total system performance at a lower cost than has been previously achieved with discrete designs or with other monolithic instrumentation amplifiers.

When operating from high source impedances, as in ECG and blood pressure monitors, the AD621 features the ideal combination of low noise and low input bias currents. Voltage noise is specified as 9 nV/(root) Hz at 1 kHz and 0.28 µV p-p from 0.1 Hz to 10 Hz. Input current noise is also extremely low at 0.1 pA/Hz. The AD621 outperforms FET input devices with an input bias current specification of 1.5 nA max over the full industrial temperature range.

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Evaluation Kits (1)

Tools & Simulations

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.

In Amp Diamond Tool

Design Tools

In-Amp Error Calculator

These tools will help estimate error contributions in your instrumentation amplifier circuit. It uses input parameters such as temperature, gain, voltage input, and source impedance to determine the errors that can contribute to your overall design.

Design Resources

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.View our quality and reliability program and certifications for more information.

Part Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
AD621ANZ Material Declaration Reliability Data 8-Lead PDIP
AD621ARZ Material Declaration Reliability Data 8-Lead SOIC
AD621ARZ-R7 Material Declaration Reliability Data 8-Lead SOIC
AD621ARZ-RL Material Declaration Reliability Data 8-Lead SOIC
AD621BNZ Material Declaration Reliability Data 8-Lead PDIP
AD621BRZ Material Declaration Reliability Data 8-Lead SOIC
AD621BRZ-R7 Material Declaration Reliability Data 8-Lead SOIC
AD621BRZ-RL Material Declaration Reliability Data 8-Lead SOIC
AD621SQ/883B Material Declaration Reliability Data 8-Lead CerDIP
Wafer Fabrication Data

PCN-PDN Information

Select a model from the dropdown below to subscribe to PCN/PDN notifications and view past notifications as well.

Sample & Buy

Ordering FAQs

See our Ordering FAQs for answers to questions about online orders, payment options and more.


Buy Now Pricing

(**) Displayed Buy Now Price and Price Range is based on small quantity orders.


List Pricing

(*)The 1Ku 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. authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


Lead Times

Please see the latest communication from our CCO regarding lead times.



Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.

Price Table Help


Evaluation Boards

Pricing displayed is based on 1-piece.

Up to two boards can be purchased through Analog.com. To order more than two, please purchase through one of our listed distributors.

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.