OPA1622 Datasheet, PDF (17/36 Pages) Texas Instruments – OPA1622 SoundPlus™ High-Fidelity, Bipolar-Input, Audio Operational Amplifier

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Feature Description (continued)
V+
+IN
+
±
± IN
OPA1622
SBOS727A – NOVEMBER 2015 – REVISED NOVEMBER 2015
EN
GND
Power Supply
ESD Cell
OUT
V±
Figure 44. Equivalent Internal ESD Circuitry
7.3.6 Input Protection
The input pins of the OPA1622 are protected from excessive differential voltage with back-to-back diodes, as
Figure 45 shows. In most circuit applications, the input protection circuitry has no consequence. However, in low-
gain or G = +1 circuits, fast-ramping input signals can forward bias these diodes because the output of the
amplifier cannot respond quickly enough to the input ramp. If the input signal is fast enough to create this
forward-bias condition, the input signal current must be limited to 10 mA or less. If the input signal current is not
inherently limited, use an input series resistor (R_I) or a feedback resistor (R_F) to limit the signal input current. This
input series resistor degrades the low-noise performance of the OPA1622 and is examined in the Noise
Performance section. Figure 45 shows an example configuration when both current-limiting input and feedback
resistors are used.
R_F
–
Input
R_I
+
Device
Output
Figure 45. Pulsed Operation
7.4 Device Functional Modes
The OPA1622 has two operating modes determined by the voltage between the enable and ground pins: a
shutdown mode (V_EN ≤ 0.78V) and an enabled mode (V_EN ≥ 0.82V). The measured datasheet performance
parameters specified in the Typical Characteristics and Specifications sections are given with the amplifier in the
enabled mode, unless otherwise noted.
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