MAX9945:38V, Low-Noise, MOS-Input, Low-Power Op Amp

Great Combination of Low Power and Low Noise in a Small Package

The MAX9945 operational amplifier features an excellent combination of low operating power and low input voltage noise. In addition, MOS inputs enable the MAX9945 to feature low input bias currents and low input current noise. The device accepts a wide supply voltage range from 4.75V to 38V and draws a low 400µA quiescent current. The MAX9945 is unity-gain stable and is capable of rail-to-rail output voltage swing. The MAX9945 is ideal for portable medical and industrial applications that require low noise analog front-ends for performance applications such as photodiode transimpedance and chemical sensor interface circuits. The MAX9945 is available in both an 8-pin µMAX® and a space-saving, 6-pin TDFN package, and is specified over the automotive operating temperature range (-40°C to +125°C).

Key Features
  • +4.75V to +38V Single-Supply Voltage Range
  • ±2.4V to ±19V Dual-Supply Voltage Range
  • Rail-to-Rail Output Voltage Swing
  • 400µA Low Quiescent Current
  • 50fA Low Input Bias Current
  • 1fA/ Low Input Current Noise
  • 15nV/ Low Noise
  • 3MHz Unity-Gain Bandwidth
  • Wide Temperature Range from -40°C to +125°C
  • Available in Space-Saving, 6-Pin TDFN Package (3mm x 3mm)
MAX9945: Typical Operating Circuit
MAX9945: Typical Operating Circuit
  • Active Filters and Signal Processing
  • Automatic Test Equipment (ATE)
  • Chemical Sensor Interface
  • Displays: Industrial, Front Panel, and Instrumentation
  • High-Performance Audio Line Out
  • Industrial Sensors and Instrumentation
  • Industrial: Process Measurement and Control
  • Medical Pulse Oximetry
  • Panel Meters
  • Photodiode Sensor Interface
  • Power Meters
  • Programmable Logic Controllers (PLCs)
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MAX9945 Data SheetMAX9945.pdf
Part NumberAmps.Rail to RailVSUPPLY (Total)
ICC per Amp.
Low Input Bias CMOS InputsInput IBIAS
Unity Gain BW
Slew Rate
minmaxtypmaxtyptypmaxtyptyp<See Notes
MAX99451Output Only4.7538400500094100Yes0.0001532.215µMAX/8
$0.93 @1k
Design kits & evaluation modules
Quality and Environmental Data
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX9945ATT+ActiveTDFN-EP,;6 pin;9.6 mm²-40°C to +125°CLead Free
MAX9945ATT+TActiveTDFN-EP,;6 pin;9.6 mm²-40°C to +125°CLead Free
MAX9945AUA+ActiveµMAX,;8 pin;15.6 mm²-40°C to +125°CLead Free
MAX9945AUA+TActiveµMAX,;8 pin;15.6 mm²-40°C to +125°CLead Free
MAX9945.pdf MAX9945
MAX9945.pdf MAX9945
MAX9945.pdf MAX9945
Improve Sensor Performance and SNR in Pulse Oximeter Designs MAXQ622
MAX9945.pdf MAX9945
MAX9945.pdf MAX9945