ADA4096-4ARUZ-RL Analog Devices, ADA4096-4ARUZ-RL Datasheet - Page 17

• Manufacturer Part Number: ADA4096-4ARUZ-RL
• Description: the ada4096-2 dual and ada4096-4 quad operational...
• Manufacturer: Analog Devices

Data Sheet
INPUT OVERVOLTAGE PROTECTION
The ADA409x family inputs are protected from input voltage
excursions up to 32 V outside each rail. This feature is of par-
ticular importance in applications with power supply sequencing
issues that could cause the signal source to be active before the
supplies to the amplifier.
Figure 52 shows the input current limiting capability of the
ADA4096-2
resistor (red curves).
Figure 52 was generated with the
ration with the supplies connected to GND (or ±15 V) and the
positive input swept until it exceeds the supplies by 32 V. In general,
input current is limited to 1 mA during positive overvoltage con-
ditions and 200 μA during negative undervoltage conditions. For
example, at an overvoltage of 20 V, the
limited to 1 mA, providing a current-limit equivalent to a series
20 kΩ resistor. Figure 52 also shows that the current limiting
circuitry is active whether the amplifier is powered or not.
–1
–2
–3
–4
–5
–6
–7
7
6
5
4
3
2
1
0
–48 –40 –32 –24 –16 –8
(green curves) compared to using a 5 kΩ series
Figure 52. Input Current Limiting Capability
V
ADA4096-2
IN
0
(V)
ADA4096-2
8
LOW RDS
5kΩ SERIES RESISTOR
16
24
in a buffer configu-
ON
32
SERIES FET
input current is
40
48
Rev. C | Page 17 of 20
Note that Figure 52 represents input protection under abnormal
conditions only. The correct amplifier operation input voltage
range (IVR) is specified in Table 2 to Table 4.
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 53).
500
400
300
200
100
0
0
4
Figure 53. Comparator Supply Current
8
12
SUPPLY VOLTAGE (V)
ADA4096-2/ADA4096-4
V
V
OUT
16
BUFFER
OUT
= HIGH
= LOW
20
24
28
32
36