I am looking into two different development boards which uses TLC2543 and ADS7870 for A to D conversion. From comparing both IC's I have found out that the resolution of both is 12 bit. However, development board manufacturer mention ADS7870 being 11 bit. The data sheet of development board using ADS7870 for A to D conversion say 11 bits are used for value and 1 bit for polarity. Is that true? Is it the case with all 12 bits A to D converters ?