Successive Approximation ADC binary output

Discussion in 'General Electronics Chat' started by x1222, Jan 18, 2012.

  1. x1222

    Thread Starter Member

    Oct 22, 2011
    I built Successive approximation ADC. As I crank up the voltage, the ADC output starts counting up binary. What is the binary output suppose to tell me? Is there anyway to convert that into readable voltage value?
  2. joeyd999

    AAC Fanatic!

    Jun 6, 2011
    You built an S/A ADC from scratch? Or you build a circuit using an off-the-shelf ADC?

    Can't help you in the first case: only you would know the answer.

    In the second case, usually you define a Vref, where the maximum number of digital counts out occurs when Vin=Vref. Then for any Vin<Vref, counts = Vin/Vref * 2^n where n is the number of bits.

    So, for, say an 8 bit ADC with a Vref of 2.56V, there will be 256 possible output values (0 to 255), each count representing a 10mV increase in Vin.
    x1222 likes this.