Datasheet

Data Sheet ADA4096-2
Rev. A | Page 17 of 20
COMPARATOR OPERATION
Although op amps are quite different from comparators,
occasionally an unused section of a dual or a quad op amp
may be pressed into service as a comparator; however, this is
not recommended for any rail-to-rail output op amps. For rail-
to-rail output op amps, the output stage is generally a ratioed
current mirror with bipolar or MOSFET transistors. With the part
operating open loop, the second stage increases the current drive
to the ratioed mirror to close the loop, but it cannot, which results
in an increase in supply current. With the op amp configured as
a comparator, the supply current can be significantly higher (see
Figure 48).
500
400
300
200
100
0 3632282420161284
0
SUPPLY CURRENT PER AMPLIFIER (µA)
SUPPLY VOLTAGE (V)
V
OUT
= HIGH
V
OUT
= LOW
BUFFER
09241-048
Figure 48. Comparator Supply Current