OPA2836-Q1 Datasheet, PDF (27/44 Pages) Texas Instruments – Very-Low Power, Rail-to-Rail Out, Negative-Rail In, Voltage-Feedback Operational Amplifier

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OPA2836-Q1
SBOS794 – DECEMBER 2016
Device Functional Modes (continued)
Figure 61 shows a similar inverting single-supply scenario with the reference generator replaced by the Thevenin
equivalent using resistors and the positive supply. R₁ and R₂ form a resistor divider from the 5-V supply and are
used to bias the positive side. To cancel the voltage offset that is otherwise caused by the input bias currents,
set the parallel sum of R₁ and R₂ equal to the parallel sum of R_F and R_G. C must be added to limit coupling of
noise into the positive input. For example, if a gain of –2 is required and R_F = 1 kΩ, select R_G = 499 Ω to set the
gain. R₁ = R₂ = 665 Ω for mid-supply voltage bias and for operational amplifier input bias current cancellation. A
good value for C is 0.1 µF and can be a lower cost compared to Figure 61, but requires extra current in the
resistor divider.
5V
5V
R₁
R_O
OPA2836-Q1
R₂
C
V_OUT
GV_SIG
2.5 V
R_G
V_SIG
2.5 V
R_F
Signal and bias to
next stage
Signal and bias
from previous stage
Copyright © 2016, Texas Instruments Incorporated
Figure 61. Inverting Single Supply With Resistors
Copyright © 2016, Texas Instruments Incorporated
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