AD8421 Instrumentation Amplifier

By Analog Devices Inc 198

AD8421 Instrumentation Amplifier

ADI's AD8421 is a low power, extremely-low noise, ultra-low bias current, high speed instrumentation amplifier, ideally suited for a broad spectrum of signal conditioning and data acquisition applications. This breakthrough product features the highest CMRR available, 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 0.7 µs settling time to 0.01% (G = 1) allow the AD8421 to amplify high-speed signals and excel in applications that require high channel-count multiplexed systems. Even at high gain, the current feedback architecture preserves this performance. For example, at G = 100, the bandwidth is 2 MHz and the settling time is 0.6 µs. The AD8421 has excellent distortion performance, allowing 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 significant source impedance, the AD8421 employs novel process technology and innovative design techniques to provide groundbreaking noise performance limited only by the sensor.

  • 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
  • Low power: 2.3 mA supply current (max.)
  • High precision DC performance (AD8421BRZ)
    • 94 dB CMRR (G = 1)(min.)
    • 0.2 µV/°C input offset voltage drift (max.)
    • 1 ppm/°C gain drift (G = 1)(max.)
    • 500 pA input bias current (max.)
  • 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)
  • Medical instrumentation
  • Precision data acquisition
  • Microphone preamplification
  • Multiplexed input applications
  • Vibration analysis
  • ADC drivers