Data Sheet
ADA4638-1
Rev. 0 | Page 19 of 24
ADA4638-1
A1
ITOTAL+
A3
ISY+
RIN1
+VSY
VOUT
–VSY
IINPUT+
RIN2
IINPUT–
A4
ISY–
A2
ITOTAL–
100
72-
06
2
Figure 62. Comparator B
system, ITOTAL, and the actual currents, ISY, that flow into and
out of the supply pins of the ADA4638-1. With RIN1 = RIN2 = 100 kΩ and supply voltage of 30 V, the total supply current of
the system is 800 μA to 900 μA.
With smaller input series resistors, total supply current of the
supply currents with RIN1 = RIN2 = 0 Ω. The total current of the
system increases to 10 mA.
ITOTAL = ISY + IINPUT
Note that, at 30 V of supply voltage, 8 mA to 9 mA of current
flows through the input pins. This is undesirable. The
ADA4638-1is not recommended to be used as a comparator. If absolutely
necessary, place resistors in series with the inputs of the ampli-
fier to limit input current to less than 10 mA.
For more details on op amps as comparators, refer to the
–1.0
–0.8
–0.6
–0.4
–0.2
0
0.2
0.4
0.6
0.8
1.0
0
5
10
15
20
25
30
CU
RRE
N
T
(
m
A
)
VSY (V)
ISY+
ITOTAL–
ITOTAL+
ISY–
100
72
-06
3
Figure 63. Supply Current vs. Supply Voltage
(Comparator A, RIN1 = RIN2 = 100 kΩ)
–1.0
–0.8
–0.6
–0.4
–0.2
0
0.2
0.4
0.6
0.8
1.0
0
5
10
15
20
25
30
CU
RRE
N
T
(
m
A
)
VSY (V)
ISY+
ITOTAL–
ITOTAL+
ISY–
10
07
2-
06
4
Figure 64. Supply Current vs. Supply Voltage
(Comparator B, RIN1 = RIN2 = 100 kΩ)
–12
–10
–8
–6
–4
–2
0
2
4
6
8
10
12
0
5
10
15
20
25
30
CUR
RE
NT
(
m
A)
VSY (V)
ISY+
ITOTAL–
ITOTAL+
ISY–
1007
2-
06
5
Figure 65. Supply Current vs. Supply Voltage
(Comparator A, RIN1 = RIN2 = 0 kΩ)
–12
–10
–8
–6
–4
–2
0
2
4
6
8
10
12
0
5
10
15
20
25
30
C
URRE
N
T
(
m
A)
VSY (V)
ISY+
ITOTAL–
ITOTAL+
ISY–
10
07
2-
0
66
Figure 66. Supply Current vs. Supply Voltage
(Comparator B, RIN1 = RIN2 = 0 kΩ)