AD620
ADI AD620 low-cost instrumentation amplifier with a single-resistor gain of 1 to 10,000, a low input bias current and a wide supply range, in an 8-lead SOIC.
The AD620 is a low-cost, low-power instrumentation amplifier from ADI that has become a standard front end for a bridge, a thermocouple and a medical sensor signal. A single external resistor sets the gain from 1 to 10,000, and the three-op-amp topology provides a high common-mode rejection ratio and a low input offset voltage with a low offset drift, so a small differential signal riding on a large common-mode voltage is recovered cleanly. The input stage holds a low input bias current, which limits the error with a high source impedance, and the output is referenced to a pin so a designer can level-shift the output to match an analog-to-digital converter. The part operates over a very wide supply range, from about ±2.3 V to ±18 V, with a supply current under about 1.3 mA, which suits a battery-powered or a portable instrument. The internally trimmed resistors keep the gain error and the common-mode rejection within a tight window without external matching, and the small SOIC package fits a dense board. Typical applications include a medical instrument such as a pulse or an ECG front end, a strain-gauge bridge, a thermocouple or an RTD measurement, a data-acquisition front end and a general precision instrumentation input. Every device BeiLuo ships is factory-traceable and includes an import declaration, a certificate of origin and a RoHS compliance file. Our FAE team helps you choose the gain and the supply and plan the layout.
FAE Professional Review
The AD620 is the classic low-cost instrumentation amplifier: one gain resistor, a high common-mode rejection and a wide supply range, which suits a bridge or a sensor front end. Its low bias current helps a high-impedance source, and the reference pin makes it easy to level-shift into an ADC. Watch the gain resistor tolerance for the overall accuracy, and keep the input pair balanced.
| Parameter | Value |
|---|---|
| Type | Instrumentation Amplifier |
| Channels | 1 |
| Bandwidth | 800 kHz |
| Supply | ±2.3 to ±18 V |
| Package | SOIC-8 |
Application Circuits
Medical sensor front ends
Reference circuits and application schematics for Medical sensor front ends are available from our FAE team.
Strain-gauge bridges
Reference circuits and application schematics for Strain-gauge bridges are available from our FAE team.
Thermocouple and RTD measurement
Reference circuits and application schematics for Thermocouple and RTD measurement are available from our FAE team.
Data-acquisition inputs
Reference circuits and application schematics for Data-acquisition inputs are available from our FAE team.
Need a reference schematic or design review? Our FAE engineers can share verified circuits and layout guidance for this part.
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Frequently Asked Questions
What projects suit the AD620?
It suits a low-cost, low-power front end for a bridge, a thermocouple or a medical sensor, where a single gain resistor and a high common-mode rejection recover a small differential signal.
Confirm the gain and the supply for your design.
How do I set the gain?
One resistor between the gain pins sets the gain from 1 to 10,000. Use a low-tolerance, low-drift resistor because the gain accuracy follows it, and keep the resistor close to the pins to reduce the noise pickup.
Read the amplifier selection guide.
Is the amplifier genuine and documented?
BeiLuo supplies factory-traceable AD620 amplifiers with an import declaration, certificate of origin and RoHS file on every order. Stock is normally available and the datasheet downloads from this page.
Order a sample to validate the amplifier before volume production.