Electronic – ny reason as to why the schematic symbol of comparators is almost equivalent to that of op amps


They do similar tasks, but they are almost completely different because comparators output digital signals. In that case, I am confused as to why their schematic symbol is almost entirely the same. Is it implying something else that I am not realizing?

Best Answer

They are not completely different. They are much more similar than you think.

Technically, a comparator is just an op-amp optimized to operate in the saturation region (have the output saturate since it is always either LO or HI, but be able to leave saturation quickly for fast switching). Being linear in the linear region is not a design priority.

An op-amp is a comparator optimized to operate in the linear region (to be very linear in the linear region where it will spend all its time due to negative feedback). An op-amp used as a comparator will be slower since it is slow to get out of saturation.

Most opamps also have frequency compensation so that they can be easily used with negative feedback. Comparators have no need for such a thing.

Those are the big ones but op-amps also tend to place higher priority on things like noise, offset, and input bias currents than comparators. All that good analog stuff.