Electronic – Interface a 5v pressure sensor with a 3.3v ADC

adcanalogdc/dc converternoise

I'm trying to interface a pressure sensor (MPXV6115vc6u) with a 3.3v ADC. My board is providing a 3.3v (it's a XBee power regulated board, via a Li-Po battery).

To wire the MPX sensor, I need to:

  1. Step-up the 3.3v to 5v to power up the sensor
  2. Convert the 0-5v analog signal to a 0-3.3v to read the pressure value.

What's the best approach, considering that pressure sensor are noise-sensitive and that my board is low-power?

For 1, I can probably use a circuit like this.

For 2, what should I do to keep the full range? What's the best way to minimize the number of components (~combine 1 and 2).


Best Answer

Since your pressure sensor only uses about 6mA according to the datasheet you might be better off with a switched capacitor step up supply like this one: http://www.ti.com/lit/ds/symlink/lm2750.pdf

To get your analog signal down to levels you can read you could just do a simple voltage divider. Or you could use an opamp this paper probably gives you more information than you'd care to know but there's a good circuit at the bottom of it: http://www.ti.com/lit/an/slyt173/slyt173.pdf

Hope that helps.