
88-11Analog-to-Digital Converters
from many places. e most common kind of noise is thermal noise, which is caused by the random
nature of electric conduction in resistors and transistors. ermal noise is worse at higher temperatures
and higher resistances. Most other ADC noise is coupled electromagnetically from nearby circuitry,
such as clock or logic circuits, or from routing of other input signals. Noise is usually specied in volts
rms or peak-to-peak, or LSBs rms or peak-to-peak.
Quantization error (see earlier) can sometimes be thought of as quantization noise. Although quan-
tization error is perfectly predictable with respect to the