Connect with us

3.3V sensor to 5V ADC

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

Scroll to continue with content
  1. sciguy14


    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


    Nov 23, 2009
  3. Resqueline


    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.
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day