AD8421
ADI AD8421 low-noise instrumentation amplifier with a 10 MHz bandwidth, a single-resistor gain and a high common-mode rejection, in an 8-lead MSOP.
The AD8421 is a low-power, low-noise instrumentation amplifier from ADI that combines a 10 MHz gain bandwidth with a low voltage noise, so a design can amplify a fast, small differential signal without adding a second stage. A single external resistor sets the gain, and the part keeps a high common-mode rejection across the bandwidth, which a current-sense or a bridge signal needs when a fast switching edge couples into the measurement. The low input voltage noise of a few nanovolts per root hertz and the low current noise suit both a low-impedance bridge and a higher-impedance source, and the output is referenced to a pin so the stage can level-shift into an analog-to-digital converter. The part operates from a supply of about ±2.5 V to ±18 V with a modest current, and its small MSOP package fits a dense board where the space is at a premium. The gain is set by one resistor, which keeps the bill of materials small, and the wide bandwidth makes the part a natural fit for a control loop that must respond quickly. Typical applications include a motor or a current-sense front end, a fast bridge or a load-cell measurement, a medical instrument, a data-acquisition input and an industrial control input that must respond in real time. 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 AD8421 brings a 10 MHz bandwidth and a low noise to the in-amp role, so it suits a current-sense or a motor-control front end that must catch a fast edge as well as a precision bridge. One gain resistor keeps the design simple, and the referenced output interfaces easily to an ADC. Watch the source impedance and the gain-resistor tolerance, and keep the layout symmetric.
| Parameter | Value |
|---|---|
| Type | Instrumentation Amplifier |
| Channels | 1 |
| Bandwidth | 10 MHz |
| Supply | ±2.5 to ±18 V |
| Package | MSOP-8 |
Application Circuits
Motor and current sensing
Reference circuits and application schematics for Motor and current sensing are available from our FAE team.
Fast bridge and load-cell measurement
Reference circuits and application schematics for Fast bridge and load-cell measurement are available from our FAE team.
Medical instruments
Reference circuits and application schematics for Medical instruments are available from our FAE team.
Real-time control inputs
Reference circuits and application schematics for Real-time control 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 AD8421?
It suits a fast, low-noise front end such as a motor or a current-sense amplifier, a fast bridge measurement or a real-time control input, where the 10 MHz bandwidth and the low noise capture a fast edge cleanly.
Confirm the gain and the supply for your design.
Why is bandwidth important here?
A current-sense or a motor signal contains a fast switching edge, so an amplifier with enough bandwidth is needed to reproduce it without distortion. The AD8421 keeps a high common-mode rejection and a low noise across its 10 MHz bandwidth.
Read the amplifier selection guide.
Is the amplifier genuine and documented?
BeiLuo supplies factory-traceable AD8421 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.