4.1.1 Thermal Drift

Another source of resistor error is thermal drift - if one resistor's temperature drift is different from the other, the error will increase as the temperature changes from the calibrated point. To avoid this effect, especially in applications at varying temperatures, the resistors must have the same temperature drift coefficient and be located as close as possible to each other to avoid temperature differentials.

Another way to handle thermal drift is to use resistor networks (or arrays). These resistors are assembled in the same package, which keeps the network closely matched in temperature. Similarly, the internal resistor ladder is built on the die of the microcontroller, which keeps it tightly matched in temperature and in terms of temperature coefficient.