The MAX9939 is a general-purpose, differential-input programmable gain amplifier (PGA) that is ideal for conditioning a variety of wide dynamic range signals such as those found in motor current-sense, medical instrumentation, and sonar data acquisition applications. It features SPI?-programmable differential gains from 0.2V/V to 157V/V, input offset voltage compensation, and an output amplifier that can be configured either as a high-order active filter or to provide a differential output.

The PGA is optimized for high-signal bandwidth and its gain can be programmed to be 0.2, 1, 10, 20, 30, 40, 60, 80, 119, and 157. Precision resistor matching provides extremely low gain tempco and high CMRR. Although the MAX9939 operates from a single supply V_CC between 2.9V to 5.5V, it can process signals both above and below ground due to use of an input levelshifting amplifier stage. Furthermore, its inputs are protected to ±16V, allowing it to withstand fault conditions and signal overranges.

The output amplifier is designed for high bandwidth and low-bias currents, making it ideal for use in multiple-feedback active filter topologies that offer much higher Qs and stop-band attenuation than Sallen-Key architectures.

The MAX9939 draws 3.4mA of quiescent supply current at 5V, and includes a software-programmable shutdown mode that reduces its supply current to only 13μA. The MAX9939 is available in a 10-pin μMAX package and operates over the -40°C to +125°C automotive temperature range.
Applications
Sensorless Motor Control
Medical Signal Conditioning
Sonar and General Purpose Data Acquisition
Differential to Single-Ended Conversion
Differential-Input, Differential-Output Signal