OPA322-Q1_17 Datasheet, PDF (17/39 Pages) Texas Instruments – 20-MHz, Low-Noise, 1.8-V, RRI/O, CMOS Operational Amplifier

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Feature Description (continued)
OPA322-Q1
OPA2322-Q1
OPA4322-Q1
SLOS856B – JUNE 2013 – REVISED MAY 2017
V+
I_OVERLOAD
10 mA, maximum
V_IN
R_S
OPA322-Q1
V_OUT
Copyright © 2016, Texas Instruments Incorporated
Figure 26. Input Current Protection
8.3.3 Phase Reversal
The OPAx322-Q1 family of op amps are designed to be immune to phase reversal when the input pins exceed
the supply voltages, which provides further in-system stability and predictability. Figure 27 shows the input
voltage exceeding the supply voltage without any phase reversal.
4
V_S = ±2.5 V
V_IN
3
2
V_OUT
1
0
-1
-2
-3
-4
-500
-250
0
250
500
Time (ms)
750 1000
Figure 27. No Phase Reversal
8.3.4 Feedback Capacitor Improves Response
For optimum settling time and stability with high-impedance feedback networks, it may be necessary to add a
feedback capacitor across the feedback resistor (R_F), as shown in Figure 28. This capacitor compensates for the
zero created by the feedback network impedance and the OPAx322-Q1 input capacitance (and any parasitic
layout capacitance). The effect becomes more significant with higher impedance networks.
C_F
R_IN
R_F
V_IN
V+
R_IN ´ C_IN = R_F ´ C_F
C_IN
OPA322-Q1
C_IN
V_OUT
C_L
Copyright © 2016, Texas Instruments Incorporated
NOTE: Where C_IN is equal to the OPAx322-Q1 input capacitance (approximately 9 pF) plus any parasitic layout capacitance.
Figure 28. Feedback Capacitor Improves Dynamic Performance
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Product Folder Links: OPA322-Q1 OPA2322-Q1 OPA4322-Q1