Data Sheet
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).
ADA4096-2
500
400
VOUT = HIGH
300
200
VOUT = LOW
100
BUFFER
0
0
4
8 12 16 20 24 28 32 36
SUPPLY VOLTAGE (V)
Figure 48. Comparator Supply Current
Rev. A | Page 17 of 20