# Binary related ADC reference voltage?

#### Veracohr

Joined Jan 3, 2011
715
In looking through the datasheet for the MAX11100 ADC I noticed that it's spec'd with a 4.096V analog reference, which sets the input voltage range. Is there some benefit to an ADC input range being related to a binary value (2^12)?

#### crutschow

Joined Mar 14, 2008
25,121
In looking through the datasheet for the MAX11100 ADC I noticed that it's spec'd with a 4.096V analog reference, which sets the input voltage range. Is there some benefit to an ADC input range being related to a binary value (2^12)?
Yes, it can simplify any subsequent math used to process the signal.
A 12 bit converter has 4096 steps making 1 LSB exactly equal to 1 mV for a 4.096V reference voltage.

• cmartinez

#### Veracohr

Joined Jan 3, 2011
715
That sounds like it simplifies characterizing the device, but for normal use? Why would it matter if 1 LSB is 1.000mV or 1.1mv? Either way it's the same digital output value.

#### crutschow

Joined Mar 14, 2008
25,121
That sounds like it simplifies characterizing the device, but for normal use? Why would it matter if 1 LSB is 1.000mV or 1.1mv? Either way it's the same digital output value.
In some applications is convenient to have have 1LSB equal to a nice even voltage.
If that doesn't matter to you then don't worry about it. #### Veracohr

Joined Jan 3, 2011
715
OK, I was just curious. Thanks.

#### cmartinez

Joined Jan 17, 2007
7,010
That sounds like it simplifies characterizing the device, but for normal use? Why would it matter if 1 LSB is 1.000mV or 1.1mv? Either way it's the same digital output value.
It's far easier perform calculations when interfacing an ADC referenced to that voltage to an MCU. Especially when dealing with assembly code and when very fast conversion rates are needed.