Overview
The AD8420ARMZ from Analog Devices Inc. is a low-cost, micropower, wide supply range instrumentation amplifier. It features a rail-to-rail output and an innovative architecture that allows for highly flexible design. The AD8420 is optimized to amplify small differential voltages in the presence of large common-mode signals, making it ideal for various applications in medical and industrial instrumentation. It operates on a single supply from 2.7 V to 36 V or dual supplies from ±2.7 V to ±18 V, and its micropower current consumption and rail-to-rail output swing make it suitable for battery-powered devices. The amplifier is available in an 8-lead MSOP package and is operational over a temperature range of -40°C to +125°C.
Key Specifications
| Parameter | Value | Conditions |
|---|---|---|
| Supply Voltage (Single/Dual) | 2.7 V to 36 V / ±2.7 V to ±18 V | |
| Maximum Supply Current | 90 μA | |
| Input Offset Voltage (Vos) | 250 μV | |
| Common Mode Rejection Ratio (CMRR) | 100 dB | |
| Gain Range | 1 to 1000 V/V | G = 1 + (R2/R1) |
| Gain Error | 0.02% to 0.1% | G = 1 to 1000, VOUT = 0.1 V to 4.8 V |
| Bandwidth (G = 100) | 2.5 kHz | |
| Input Voltage Noise | 55 nV/√Hz | |
| Output Swing | (-VS + 100 mV) to (+VS - 150 mV) | RL = 20 kΩ |
| Operating Temperature Range | -40°C to +125°C | |
| Package | 8-Lead MSOP |
Key Features
- Rail-to-Rail Output: The output voltage swing is completely independent of the input common-mode voltage, maximizing dynamic range even at low supply voltages.
- Wide Supply Range: Operates on single supply from 2.7 V to 36 V or dual supplies from ±2.7 V to ±18 V.
- Micropower Current Consumption: Maximum supply current of 90 μA, making it ideal for battery-powered applications.
- High CMRR: Common Mode Rejection Ratio of 100 dB, ensuring excellent rejection of common-mode signals.
- Flexible Gain Setting: Gain is set with two external resistors, allowing for a gain range of 1 to 1000 V/V.
- Low Drift Characteristics: Suitable for applications requiring low gain drift and high precision.
- Input Range Below Ground: Can amplify signals at or even slightly below ground without requiring dual supplies.
Applications
- Bridge Amplifiers: Ideal for amplifying small differential voltages in bridge configurations.
- Pressure Measurement: Used in pressure measurement systems due to its high precision and low drift characteristics.
- Medical Instrumentation: Suitable for medical devices requiring high accuracy and low power consumption.
- Portable Data Acquisition: Ideal for portable data acquisition systems due to its low power consumption and wide supply range.
- Multichannel Systems: Can be used in multichannel systems where high precision and flexibility are required.
Q & A
- What is the supply voltage range for the AD8420?
The AD8420 operates on a single supply from 2.7 V to 36 V or dual supplies from ±2.7 V to ±18 V.
- What is the maximum supply current of the AD8420?
The maximum supply current is 90 μA.
- What is the gain range of the AD8420?
The gain range is from 1 to 1000 V/V, set by two external resistors.
- What is the common mode rejection ratio (CMRR) of the AD8420?
The CMRR is 100 dB.
- Can the AD8420 amplify signals below ground without dual supplies?
Yes, the AD8420 can amplify signals at or even slightly below ground without requiring dual supplies.
- What is the output swing of the AD8420?
The output swing is from (-VS + 100 mV) to (+VS - 150 mV).
- What is the operating temperature range of the AD8420?
The operating temperature range is from -40°C to +125°C.
- In what package is the AD8420 available?
The AD8420 is available in an 8-lead MSOP package.
- What are some typical applications of the AD8420?
Typical applications include bridge amplifiers, pressure measurement, medical instrumentation, portable data acquisition, and multichannel systems.
- How does the AD8420 handle capacitive loads?
The AD8420 can drive heavy capacitive loads up to approximately 700 pF.
