–0.5

Common-Mode Voltage (V)

OFFSET VOLTAGE

vs FULL COMMON-MODE VOLTAGE RANGE

0

V–

0.5

1.5

1

2.5

2

3.5

3

4.5

5

4

5.5

2

1.5

1

0.5

0

–0.5

–1

–1.5

–2

V+

5V

0V

G = +1V/V, V

10µs/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

8

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