Overview
The AD8421BRMZ-R7, produced by Analog Devices Inc., is a low-cost, low-power, extremely low-noise, ultra-low bias current, high-speed instrumentation amplifier. It is designed for a broad spectrum of signal conditioning and data acquisition applications. This amplifier is notable for its high common-mode rejection ratio (CMRR), low noise, and high precision DC performance, making it ideal for extracting low-level signals in the presence of high-frequency common-mode noise over a wide temperature range.
Key Specifications
| Parameter | Unit | Min | Typ | Max |
|---|---|---|---|---|
| Supply Voltage | V | ±2.5 | ±18 (5 V to 36 V single supply) | |
| Input Bias Current | pA | 0.1 | 500 | 8 (over temperature) |
| Input Offset Voltage | µV | 50 | 70 | 135 (over temperature) |
| Input Offset Voltage Drift | µV/°C | 0.2 | ||
| Gain Drift | ppm/°C | 1 | ||
| CMRR at 20 kHz (G = 1) | dB | 80 | ||
| Bandwidth (G = 1) | MHz | 10 | ||
| Bandwidth (G = 100) | MHz | 2 | ||
| Slew Rate | V/µs | 35 | ||
| Settling Time to 0.001% (G = 10) | µs | 0.6 | ||
| Input Voltage Noise at 1 kHz | nV/√Hz | 3.2 | ||
| Current Noise at 1 kHz | fA/√Hz | 200 | ||
| Quiescent Current | mA | 2.3 | ||
| Operating Temperature Range | °C | -40 | +85 (MSOP, SOIC), +125 (LFCSP) |
Key Features
- Low power consumption with a maximum supply current of 2.3 mA.
- Extremely low noise: 3.2 nV/√Hz input voltage noise and 200 fA/√Hz current noise at 1 kHz.
- High CMRR: up to 94 dB minimum at G = 1.
- High precision DC performance with low input offset voltage drift (0.2 µV/°C) and low gain drift (1 ppm/°C).
- High-speed performance: 10 MHz bandwidth at G = 1, 2 MHz at G = 100, and 0.6 µs settling time to 0.001% at G = 10.
- 35 V/µs slew rate.
- Inputs protected to 40 V from the opposite supply rail.
- Gain settable with a single resistor from 1 to 10,000.
- Available in 8-lead LFCSP, 8-lead MSOP, and 8-lead SOIC packages.
Applications
- Medical instrumentation.
- Precision data acquisition.
- Microphone preamplification.
- Vibration analysis.
- Multiplexed input applications.
- ADC driver.
Q & A
- What is the typical input voltage noise of the AD8421? The AD8421 has a typical input voltage noise of 3.2 nV/√Hz at 1 kHz.
- What is the maximum input bias current of the AD8421? The maximum input bias current is 500 pA.
- What is the CMRR of the AD8421 at 20 kHz with a gain of 1? The CMRR is 80 dB at 20 kHz with a gain of 1.
- What is the settling time of the AD8421 to 0.001% at a gain of 10? The settling time is 0.6 µs to 0.001% at a gain of 10.
- What are the available package types for the AD8421? The AD8421 is available in 8-lead LFCSP, 8-lead MSOP, and 8-lead SOIC packages.
- What is the operating temperature range for the AD8421 in MSOP and SOIC packages? The operating temperature range is -40°C to +85°C for MSOP and SOIC packages.
- Can the gain of the AD8421 be set with a single resistor? Yes, the gain can be set with a single resistor from 1 to 10,000.
- What is the slew rate of the AD8421? The slew rate is 35 V/µs.
- What are some typical applications of the AD8421? Typical applications include medical instrumentation, precision data acquisition, microphone preamplification, vibration analysis, and multiplexed input applications.
- How is the input protection of the AD8421? The inputs are protected to 40 V from the opposite supply rail.
