Opamp recommendaion please

Discussion in 'The Projects Forum' started by cork_ie, Aug 15, 2014.

  1. cork_ie

    Thread Starter Active Member

    Oct 8, 2011
    Hello all.
    My latest project(plaything) is a 3 axis +/- 3g accelerometer based on the ADXL330.
    I am using a board with a 3.3V power supply. 0g on each axis is approximately half that, 1.66 V , my maximum range is going to be 0V to 3.3V. signal on each output.
    My Board specs are:
    Triple axis =/-3g sense range.
    Upto 360mV/g sensitivity
    500Hz bandwidth
    Internal 3.3V regulator
    External operating voltage 3.5V to 15V
    Integrated power supply decoupling
    Draws 0.9mA
    Can accurately drive 500Ohm Loads

    What I would like to do is use a suitable OpAmp so that I can offset 0g to 0Volts and also amplify my signals so the output voltage range would be close to +/- 5V , i.e. + 3g=5V 0g=0V -3g=-5v . My outputs will normally be feeding 3 channels of my 4 channel Picoscope
    Datasheet attached

    Can anyone recommend a suitable low noise Opamp, ideally one that can handle all three inputs.
    Last edited: Aug 15, 2014
  2. cork_ie

    Thread Starter Active Member

    Oct 8, 2011
    Has no one any ideas or suggestions on this?
  3. ronv

    AAC Fanatic!

    Nov 12, 2008
    You will need to buffer the output of the 330 with a unity gain buffer. The output is really pretty high so I wouldn't worry to much about a real low noise amplifier. You can then follow the buffer with a gain of 1.5 or so. Reference the + input of the amplifier to a voltage divider of 1/2 Vcc. If you want it real accurate you may need a pot on this divider to zero out the initial error of the 0 G output of the 333. Plus and minus 15 volt supplies and something like two TL083's should work pretty good.
    cork_ie likes this.