AN1812 datasheet(13/34 Pages) STMICROELECTRONICS

13 / 34 page

AN1812

7 Error analysis / constraints

13/34

the conversion time and the better the accuracy will be. So there is always a trade-off between

conversion time and accuracy.

7.5

16-bit TIMER

A 16-bit timer is used as the counter that measures the conversion time. Overflows are also

taken into account, so we can also use an 8-bit timer. The resolution of the ADC depends on

the operating frequency of the timer.

7.6

Effect of temperature

The value and characteristics of each component vary with temperature. The effect of

temperature can be broadly categorized as offset drift and gain drift. So we need to

compensate the ADC for each significant change in temperature.

7.7

Comparator

The comparators are the cornerstone of the A/D conversion process. The ability of the

comparator to detect small voltage/current changes makes the comparator very important in

the

A/D conversion process. So any degradation of the intended behaviour of the comparator,

which is most usually caused by unwanted noise, will lead to the degradation of the ADC’s

ability to measure low voltages.

AN1812 Datasheet(PDF) 13 Page - STMicroelectronics