
Very popular in portable systems with lowvoltage supply (3 V and less), where the usual op
amps cannot provide a large output swing.

The input range can be set so that the signal
only goes to within a few hundred millivolts of
each rail. Often, there is a demand for op amps
with an input voltage that includes both supply
rails, i.e.. rail-to-rail operation

In many single-supply applications it is required
that the input common-mode voltage range
extends to one of the supply rails (usually
negative rail or ground).