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AD8421
RECOMMENDED FOR NEW DESIGNS3 nV /√Hz, Low Power Instrumentation Amplifier
- Part Models
- 17
- 1ku List Price
- Starting From $2.77
Part Details
- Low power
- 2.3 mA maximum supply current
- Low noise
- 3.2 nV/√Hz maximum input voltage noise at 1 kHz
- 200 fA/√Hz current noise at 1 kHz
- Excellent ac specifications
- 10 MHz bandwidth (G = 1)
- 2 MHz bandwidth (G = 100)
- 0.6 µs settling time to 0.001% (G = 10)
- 80 dB CMRR to 20 kHz (G = 1)
- 35 V/µs slew rate
- High precision dc performance (AD8421BRZ)
- 94 dB CMRR minimum (G = 1)
- 0.2 μV/°C maximum input offset voltage drift
- 1 ppm/°C maximum gain drift (G = 1)
- 500 pA maximum input bias current
- Inputs protected to 40 V from opposite supply
- ±2.5 V to ±18 V dual supply (5 V to 36 V single supply)
- Gain set with a single resistor (G = 1 to 10,000)
- Available in 8-lead LFCSP, 8-lead MSOP, and 8-lead SOIC
- Download AD8421-KGD Data Sheet
- Available As Known Good Die and fully guaranteed to data sheet specifications
AD8421-EP supports defense and aerospace applications (AQEC standard)
- Download AD8421-EP data sheet (pdf)
- Military temperature range (−55°C to +125°C)
- Controlled manufacturing baseline
- One assembly/test site
- One fabrication site
- Enhanced product change notification
- Qualification data available on request
- V62/13625 DSCC Drawing Number
The AD8421 is a low cost, low power, extremely low noise, ultralow bias current, high speed instrumentation amplifier that is ideally suited for a broad spectrum of signal conditioning and data acquisition applications. This product features extremely high CMRR, allowing it to extract low level signals in the presence of high frequency common-mode noise over a wide temperature range.
The 10 MHz bandwidth, 35 V/µs slew rate, and 0.6 µs settling time to 0.001% (G = 10) allow the AD8421 to amplify high speed signals and excel in applications that require high channel count, multiplexed systems. Even at higher gains, the current feedback architecture maintains high performance; for example, at G = 100, the bandwidth is 2 MHz and the settling time is 0.8 µs. The AD8421 has excellent distortion performance, making it suitable for use in demanding applications such as vibration analysis.
The AD8421 delivers industry-leading 3 nV/√Hz input voltage noise and 200 fA/√Hz current noise with only 2 mA quiescent current, making it an ideal choice for measuring low level signals. For applications with high source impedance, the AD8421 employs innovative process technology and design techniques to provide noise performance that is limited only by the sensor.
The AD8421 uses unique protection methods to ensure robust inputs while still maintaining very low noise. This protection allows input voltages up to 40 V from the opposite supply rail without damage to the part.
A single resistor sets gains between 1 and 10,000. The reference pin can be used to apply a precise offset to the output voltage.
The AD8421 performance is specified from −40°C to +85°C for the 8-lead MSOP and SOIC packages, and from −40°C to 125°C for the 8-lead LFCSP package.
Applications
- Medical instrumentation
- Precision data acquisition
- Microphone preamplification
- Vibration analysis
- Multiplexed input applications
- ADC driver
Documentation
Data Sheet 4
Application Note 2
Technical Articles 2
Technical Book 1
Rarely Asked Question Page 2
Student Zone Article page 1
Webcast 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. View our quality and reliability program and certifications for more information.
| Part Model | Pin/Package Drawing | Documentation | CAD Symbols, Footprints, and 3D Models |
|---|---|---|---|
| AD8421-KGD-WP | CHIPS OR DIE | ||
| AD8421ACPZ-R7 | 8-Lead LFCSP (3mm x 3mm w/ EP) | ||
| AD8421ACPZ-RL | 8-Lead LFCSP (3mm x 3mm w/ EP) | ||
| AD8421ARMZ | 8-Lead MSOP | ||
| AD8421ARMZ-R7 | 8-Lead MSOP | ||
| AD8421ARMZ-RL | 8-Lead MSOP | ||
| AD8421ARZ | 8-Lead SOIC | ||
| AD8421ARZ-R7 | 8-Lead SOIC | ||
| AD8421ARZ-RL | 8-Lead SOIC | ||
| AD8421BRMZ | 8-Lead MSOP | ||
| AD8421BRMZ-R7 | 8-Lead MSOP | ||
| AD8421BRMZ-RL | 8-Lead MSOP | ||
| AD8421BRZ | 8-Lead SOIC | ||
| AD8421BRZ-R7 | 8-Lead SOIC | ||
| AD8421BRZ-RL | 8-Lead SOIC | ||
| AD8421TRMZ-EP | 8-Lead MSOP | ||
| AD8421TRMZ-EP-R7 | 8-Lead MSOP |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
| No Match Found | ||
|
Apr 4, 2023 - 22_0142 Qualification of an Alternate Wafer Fab for High Voltage Bipolar Products (HVBIP) to Analog Devices, Inc. Wilmington MA |
||
| AD8421-KGD-WP | PRODUCTION | |
| AD8421ACPZ-R7 | PRODUCTION | |
| AD8421ACPZ-RL | PRODUCTION | |
| AD8421ARMZ | PRODUCTION | |
| AD8421ARMZ-R7 | PRODUCTION | |
| AD8421ARMZ-RL | PRODUCTION | |
| AD8421ARZ | PRODUCTION | |
| AD8421ARZ-R7 | PRODUCTION | |
| AD8421ARZ-RL | PRODUCTION | |
| AD8421BRMZ | PRODUCTION | |
| AD8421BRMZ-R7 | PRODUCTION | |
| AD8421BRMZ-RL | PRODUCTION | |
| AD8421BRZ | PRODUCTION | |
| AD8421BRZ-R7 | PRODUCTION | |
| AD8421BRZ-RL | PRODUCTION | |
| AD8421TRMZ-EP | PRODUCTION | |
| AD8421TRMZ-EP-R7 | ||
This is the most up-to-date revision of the Data Sheet.
Hardware Ecosystem
-
Differential Voltage Measurement -
Low Power Strain Gauge Signal Measurement -
Precision Differential Voltage Measurement
Tools & Simulations
LTspice 1
Models for the following parts are available in LTspice:
- AD8421
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.
Open ToolSignal Chain Designer - BETA
Signal Chain Designer is a web-based tool designed to create and simulate complex precision signal chains. See your circuit’s performance before you commit to your PCB: transfer function, noise, power consumption, input range, and DC error. Quickly experiment with different parts and architectures. Signal chains can be exported to LTspice for further analysis.
Open ToolSPICE Model 1
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.
Evaluation Kits
AD62x, AD822x, AD842x Series InAmp Evaluation Board
Resources
High-Performance Precision Impedance Analyzer Measurement Module
Resources
Software
Reference Designs
High Precision, Wide Bandwidth Current Measurement Signal Chain