Overview
The AD8221ARM, produced by Analog Devices Inc., is a gain programmable, high-performance instrumentation amplifier. It stands out for delivering the industry’s highest common-mode rejection ratio (CMRR) over frequency in its class. This amplifier maintains a minimum CMRR of 80 dB up to 10 kHz for all grades at a gain of 1, significantly reducing the need for additional filtering to reject wideband interference and line harmonics.
The AD8221ARM is designed for applications requiring high DC performance, including low voltage offset, low offset drift, low gain drift, and high gain accuracy. It operates on both single and dual supplies, with a wide power supply range of ±2.3 V to ±18 V, and is specified over the entire industrial temperature range of −40°C to +85°C.
Key Specifications
| Parameter | Conditions | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Common-Mode Rejection Ratio (CMRR) | DC to 60 Hz, G = 1 | 80 | 90 | - | dB |
| CMRR at 10 kHz | G = 1 | 80 | 80 | - | dB |
| Input Offset Voltage | - | - | 25 | - | µV |
| Input Offset Drift | - | - | 0.3 | - | µV/°C |
| Input Bias Current | - | 0.5 | 2 | - | nA |
| Power Supply Range | - | ±2.3 V | - | ±18 V | V |
| Operating Temperature | - | -40°C | - | +85°C | °C |
| -3 dB Bandwidth | G = 1 | 825 | - | - | kHz |
| Slew Rate | - | 2 | - | - | V/µs |
| Noise (RTI) | @ 1 kHz | - | 8 | - | nV/√Hz |
Key Features
- Gain programmable with a single external resistor (gain range 1 to 1000).
- High CMRR over frequency, maintaining 80 dB minimum CMRR to 10 kHz at G = 1.
- Low voltage offset, low offset drift, and low gain drift.
- Wide power supply range: ±2.3 V to ±18 V.
- Operational over the entire industrial temperature range of −40°C to +85°C and up to 125°C.
- Available in 8-lead SOIC and 8-lead MSOP packages, with the MSOP requiring half the board space of the SOIC).
- High accuracy DC performance, including low input bias current and low noise).
Applications
- Weigh scales).
- Industrial process controls).
- Bridge amplifiers).
- Precision data acquisition systems).
- Medical instrumentation).
- Strain gages and transducer interfaces).
- Biomedical analysis and aerospace instrumentation).
Q & A
- What is the CMRR of the AD8221 at 10 kHz?
The AD8221 maintains a minimum CMRR of 80 dB at 10 kHz for all grades at a gain of 1).
- How is the gain of the AD8221 set?
The gain of the AD8221 is set using a single external resistor across the RG pins, with the gain formula being G = 1 + (49.4 kΩ/RG)).
- What are the available package options for the AD8221?
The AD8221 is available in 8-lead SOIC and 8-lead MSOP packages, with the MSOP requiring half the board space of the SOIC).
- What is the operating temperature range of the AD8221?
The AD8221 is specified over the entire industrial temperature range of −40°C to +85°C and is operational up to 125°C).
- What is the power supply range of the AD8221?
The AD8221 operates with a wide power supply range of ±2.3 V to ±18 V).
- What are some typical applications of the AD8221?
Typical applications include weigh scales, industrial process controls, bridge amplifiers, precision data acquisition systems, medical instrumentation, and strain gages).
- What is the slew rate of the AD8221?
The slew rate of the AD8221 is 2 V/µs).
- What is the input offset voltage of the AD8221?
The maximum input offset voltage of the AD8221 is 25 µV).
- What is the input bias current of the AD8221?
The input bias current of the AD8221 is typically 0.5 nA).
- How does the AD8221 compare to other instrumentation amplifiers in terms of CMRR?
The AD8221 has a significantly higher CMRR over frequency compared to other instrumentation amplifiers like the LT1167 and INA129, offering better performance at a lower cost).
