Tags: ADC, education, LSB, least significant bit, theory
For an ADC, a value of the LSB is calculated as follows:
where N is a number of bits. “Input voltage range” is the difference between maximum and minimum voltage values that ADC is able to convert. “Input voltage range” may be rail-to-rail and equal to VDD – VGND.
Fig. 37 presents the transfer response of an ideal 3-bit ADC. Using the given definition of LSB, the LSB for the ADC is equal to:
Thus, one least significant bit LSB is equal to an analog value of 0.5 V:
1 LSB = 0.5 V
Figure 37: Transfer curve of an ideal 3-bit ADC, where power supply VDD is equal to 4V.