SPI-Programmable Gain Amplifier (PGA) with Input VOS Trim and Output Op Amp

Programmable Gain Amplifier with SPI Interface Suitable for a Wide Range of Applications


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 0.2V/V, 1V/V, 10V/V, 20V/V, 30V/V, 40V/V, 60V/V, 80V/V, 119V/V, and 157V/V. Precision resistor matching provides extremely low gain tempco and high CMRR. Although the MAX9939 operates from a single supply VCC between 2.9V to 5.5V, it can process signals both above and below ground due to the use of an input level-shifting 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 stopband 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.
MAX9939: Functional Diagram MAX9939: Functional Diagram Enlarge+

Key Features

  • SPI-Programmable Gains: 0.2V/V to 157V/V
  • Extremely Low Gain Tempco
  • Integrated Amplifier for R/C Programmable Active Filter
  • Input Offset-Voltage Compensation
  • Input Protection to ±16V
  • 13µA Software Shutdown Mode
  • -40°C to +125°C Operating Temperature Range
  • 10-Pin µMAX Package


  • Amplification
  • Differential to Single-Ended Conversion
  • Differential-Input, Differential-Output Signal
  • Medical Signal Conditioning
  • Sensor Interface and Signal Processing
  • Sensorless Motor Control
  • Sonar and General Purpose Data Acquisition
Part Number Interface Type AV
Gain Error
Gain Temp.- Coeff.
Shutdown Mode Supply Current
Shutdown Mode Supply Current
Supply Current
Supply Current
Gain-BW Product
Oper. Temp.
max max min max typ max typ max See Notes
MAX9939  SPI 0.2 to 157 0.38 17 2.9 5.5 13 24 3400 6700 2.15 to 279 -40 to +125 $1.06 @1k
See All Programmable Gain Amplifiers (2)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

MAX9939EVKIT: Evaluation Kit for the MAX9939

Tools & Models

MAX9939 EVKIT Software


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