high current, low noise and distortion linear amplifier design

Thread Starter


Joined Nov 11, 2009
Application: We are making a long range nanopositioning system with range 10mm and resolution 10nm. The mechanism is actuated by voice coil motor which needs a amplifier driver. The driver has to deliver high current (for range) with ultra low noise and distortion (for resolution).

Specifications for amplifier circuit:
1. Max current : 10A
2. Bandwidth : 200Hz (my only hope to achieve other specifications!)
3. Noise Floor : -110dB
4. Total harmonic Distortion > 100dB

Q) Is it possible to design an power amplifier circuit with such noise specifications?
Q) Is using composite amplifier design in which the power opamp is preceded by a precision op amp can offer better noise and distortion performance from the overall circuit?
Q) How can I simulate noise and distortion any op amp circuit? Is there a solution in PSpice?


Joined Dec 20, 2007
The very best audio amps have distortion at 0.003% at full power which is -90dB.
If you chop off all the high frequencies above 200hz then the distortion will be lower.