Programmable Differential Amplifiers

 

World's First Programmable Differential Amplifier

Industry's First Programmable Differential Amplifiers

Texas Instruments has developed a new breed of amplifier, the programmable differential amplifier (PDA), combining the best of fully differential amplifiers (FDAs) and variable gain amplifiers (VGAs).

The LMH688x provide optimized noise, distortion, and bandwidth performance over a 6 dB to 26 dB gain range, giving system designers a single device for use in many applications. Now engineers can easily modify designs by varying gain without having to change external resistors, choose different amplifiers, or reconfigure and optimize each gain stage, changing the way they design with differential amplifiers.

Designing with PDAs increases flexibility and significantly reduces design time, solution size, and BOM cost for a broad range of applications including medical, test and measurement, military, wireless communications, and microwave backhaul.

Related Products

Noise Figure vs Gain at 100 MHz

Noise Figure vs Gain

LMH688x offer better and much more consistent noise and distortion performance over the entire gain range



PDAs vs FDAs and DVGAs

Feature LMH688x PDA FDA DVGA
  LMH688x PDA FDA DVGA
Gain control
  • Superior flexibility and accuracy
  • SPI control or dedicated pins
  • Need to change external resistors for each gain setting
  • Programmable gain control
Noise/distortion performance
  • Maintains noise and distortion performance over entire gain range
  • Noise figure dependent on external resistors and changes with gain
  • Noise figure increases dB-for-dB as gain is decreased from maximum gain
External resistors
  • No need for external resistors
  • Four precision external resistors required per amplifier
  • No need for external resistors
Bandwidth
  • Nearly constant across gain range
  • Bandwidth goes down as gain goes up
  • Nearly constant across gain

Featured Products

LMH6881 – Single programmable differential amplifier with gain control for general purpose

LMH6882 – Dual programmable differential amplifier with gain control and accurate ch-to-ch gain/phase matching for ZIF applications

Brochures

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