ADA4610-2ACPZ-R7 AD [Analog Devices], ADA4610-2ACPZ-R7 Datasheet - Page 15

• Manufacturer Part Number: ADA4610-2ACPZ-R7
• Description: Low Noise, Precision, Rail-to-Rail Output
• Manufacturer: AD [Analog Devices]

Data Sheet
APPLICATIONS INFORMATION
COMPARATOR OPERATION
Although op amps are quite different from comparators,
occasionally an unused section of a dual or a quad op amp may
be used as a comparator; however, this is not recommended for
any rail-to-rail output op amp. 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. However, the second stage cannot close the loop,
which results in an increase in supply current. With the op amp
configured as a comparator, the supply current can be signifi-
cantly higher (see Figure 45). Configuring an unused section as
a voltage follower with the noninverting input connected to a
voltage within the input voltage range is recommended. The
ADA4610-2
excess supply current, but does not entirely eliminate this effect
when the op amp is operating open loop.
V
V
IN+
IN–
DE4
DE3
has a unique output stage design that reduces the
DE2
DE1
C3
Q8
Q1
J1
R6
R2
Q7
J2
Q9
Q4
R7
R3
Q5
Q6
R5
I
2
A1
+ –
Figure 46. Simplified Schematic
Q23
Rev. A | Page 15 of 20
Q12
I
3
Q30
Q14
Q24
Q13
R10
Q16
8
7
6
5
4
3
2
1
0
Q29
Q15
Q25
0
R11
COMPARATOR, V
Figure 45. Supply Current vs. Supply Voltage
4
Q17
Q18
I
4
8
OUT
1+
COMPARATOR, V
SUPPLY VOLTAGE (V)
A2
12
= LOW
RC4
16
FOLLOWER
R16
D31
R16
D26
C4
20
OUT
C2
C1
= HIGH
24
Q28
Q27
ADA4610-2
28
DE5
DE6
V
V
32
V
CC
EE
OUT