GENERAL DESCRIPTION

The AD8421is a low cost, low power, extremely low noise, ultra low 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 AD8421to 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

AD8421has excellent distortion performance, making it suitable for use in demanding applications such as vibration analysis.

FEATURES

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 at 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)

APPLICATIONS

Medical instrumentation

Precision data acquisition

Microphone preamplification

Vibration analysis

Multiplexed input applications

ADC driver

SPECIFICATIONS

VS= ±15 V, VREF= 0 V, TA= 25°C, G = 1, RL= 2 kΩ, unless otherwise noted.