Datasheet

–
0.5
Offset Voltage (mV)
Common-Mode Voltage (V)
OFFSET VOLTAGE
vs FULL COMMON-MODE VOLTAGE RANGE
0
V–
0.5 1.51 2.52 3.53 4.5 54 5.5
2
1.5
1
0.5
0
–0.5
–1
–
1.5
–2
V+
5V
1V/div
0V
G = +1V/V, V
S
= +5V
10
µ
s/div
V
IN
V
OUT
5kW
1/2
OPA2348
10mA max
+5V
V
IN
V
OUT
I
OVERLOAD
OPA2348-Q1
OPA4348-Q1
SBOS465A –JANUARY 2009–REVISED MARCH 2010 www.ti.com
Figure 2. Behavior of Typical Transition Region at Room Temperature
Rail-to-Rail Input
The input common-mode range extends from (V–) – 0.2 V to (V+) + 0.2 V. For normal operation, inputs should
be limited to this range. The absolute maximum input voltage is 500 mV beyond the supplies. Inputs greater than
the input common-mode range but less than the maximum input voltage, while not valid, do not cause any
damage to the op amp. Unlike some other op amps, if input current is limited the inputs may go beyond the
power supplies without phase inversion, as shown in Figure 3.
Figure 3. No Phase Inversion With Inputs Greater Than Power-Supply Voltage
Normally, input currents are 0.5 pA. However, large inputs (greater than 500 mV beyond the supply rails) can
cause excessive current to flow in or out of the input pins. Therefore, as well as keeping the input voltage below
the maximum rating, it is also important to limit the input current to less than 10 mA. This is easily accomplished
with an input voltage resistor, as shown in Figure 4.
Figure 4. Input Current Protection for Voltages Exceeding the Supply Voltage
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