PRODUCT DESCRIPTION
The AD621 is an easy to use, low cost, low power, high accuracy instrumentation amplifier that is ideally suited for a wide range of applications. Its unique combination of high performance, small size and low power, outperforms discrete in amp implementations. High functionality, low gain errors, and low gain drift errors are achieved by the use of internal gain setting resistors. Fixed gains of 10 and 100 can easily be set via external pin strapping. The AD621 is fully specified as a total system, therefore, simplifying the design process.
For portable or remote applications, where power dissipation, size, and weight are critical, the AD621 features a very low supply current of 1.3 mA max and is packaged in a compact 8-lead SOIC, 8-lead plastic DIP or 8-lead cerdip. The AD621 also excels in applications requiring high total accuracy, such as precision data acquisition systems used in weigh scales and transducer interface circuits. Low maximum error specifications including nonlinearity of 10 ppm, gain drift of 5 ppm/°C, 50 µV offset voltage, and 0.6 µV/°C offset drift (“B” grade), make possible total system performance at a lower cost than has been previously achieved with discrete designs or with other monolithic instrumentation amplifiers.
When operating from high source impedances, as in ECG and blood pressure monitors, the AD621 features the ideal combination of low noise and low input bias currents. Voltage noise is specified as 9 nV/√Hz at 1 kHz and 0.28 µV p-p from 0.1 Hz to 10 Hz. Input current noise is also extremely low at 0.1 pA/√Hz.
The AD621 outperforms FET input devices with an input bias current specification of 1.5 nA max over the full industrial temperature range.

FEATURES
   EASY TO USE
   Pin-Strappable Gains of 10 and 100
   All Errors Specified for Total System Performance
   Higher Performance than Discrete In Amp Designs
   Available in 8-Lead DIP and SOIC
   Low Power, 1.3 mA Max Supply Current
   Wide Power Supply Range (±2.3 V to ±18 V)

EXCELLENT DC PERFORMANCE
   0.15% Max, Total Gain Error
   ±5 ppm/°C, Total Gain Drift
   125 μV Max, Total Offset Voltage
   1.0 μV/°C Max, Offset Voltage Drift

LOW NOISE
   9 nV/√Hz, @ 1 kHz, Input Voltage Noise
   0.28 μV p-p Noise (0.1 Hz to 10 Hz)

EXCELLENT AC SPECIFICATIONS
   800 kHz Bandwidth (G = 10), 200 kHz (G = 100)
   12 μs Settling Time to 0.01%

APPLICATIONS
   Weigh Scales
   Transducer Interface and Data Acquisition Systems
   Industrial Process Controls
   Battery-Powered and Portable Equipment