OPA4188 Datasheet, PDF (21/35 Pages) Texas Instruments – Zero-Drift Operational Amplifiers

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OPA4188
SBOS641C – JUNE 2012 – REVISED NOVEMBER 2015
Typical Applications (continued)
This circuit produces a signal inversion. For this circuit, use Equation 2 to calculate the gain at DC and the low-
pass cutoff frequency.
Gain ^R4
R₁
f_C
1
2S
1 R₃R₄C₂C₅
(2)
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9.2.1.3 Application Curve
20
0
-20
-40
-60
100
1k
10k
100k
1M
Frequency (Hz)
Figure 45. Gain (dB) vs Frequency (Hz)
9.2.2 Discrete INA + Attenuation for ADC With a 3.3-V Supply
Figure 46 illustrates a circuit with high input impedance that can accommodate ±2 V differential input signals. The
output, V_OUT, is scaled into the full scale input range of a 3.3 V analog to digital converter. Input common mode
voltages as high as ±10 V can be present with no signal clipping. Input stage gain is determined by resistors R₅,
R_G and R₇ according to Equation 3 .
Gain 0.2x ^{R5 R7}
R_G
(3)
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