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3.3V sensor to 5V ADC

Discussion in 'Sensors and Actuators' started by sciguy14, Nov 23, 2009.

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  1. sciguy14

    sciguy14

    2
    0
    Nov 23, 2009
    Hi there!

    I have some 3.3V sensors with analog outputs that I would like to interface to a 5V ADC converter, while maintaining full resolution. ie, I don't want to just give up the range of digital values generated between 3.3V an 5V. An example of one of these sensors is a 3 axis accelerometer, with an analog output for each axis. You can view the data sheet here:

    The ADC expects a value between 0 and 5V volts (analog), so if I just send in the 3.3Vmax signal, I'll be wasting valuable resolution. How can I proportionally amplify the 3.3V sensor output so it ranges from 0 to 5V?

    Thanks so much!!!
     
  2. sciguy14

    sciguy14

    2
    0
    Nov 23, 2009
  3. Resqueline

    Resqueline

    2,848
    2
    Jul 31, 2009
    Looking at the datasheet it doesn't seem to me that it's so accurate that losing 1 bit wold matter very much, unless you're using an 8-bit ADC.
    That being said it's just a matter of adding 3 non-inverting op-amps with a gain of 5/3.3=1.515 to the outputs. They must of course be supplied by 5V or more, and they could be made somewhat adjustable to make the MMA accurate before digitizing.
     
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