OPA4277-SP Datasheet, PDF (12/21 Pages) Texas Instruments – High-Precision Operational Amplifier

OPA4277-SP
SBOS771 – DECEMBER 2016
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Feature Description (continued)
When the bias current is canceled in this manner, the input bias current and input offset current are
approximately the same magnitude. As a result, it is not necessary to use a bias current cancellation resistor, as
is often done with other operational amplifiers (see Figure 21). A resistor added to cancel input bias current
errors may actually increase offset voltage and noise.
R₂
R₂
R₁
R₁
Op Amp
OPA4277-SP
R_B = R₂ || R₁
No bias current
cancellation resistor
(see text)
(a)
(b)
Conventional op amp with external bias
current cancellation resistor.
OPA4277-SP with no external bias
current cancellation resistor.
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Figure 21. Input Bias Current Cancellation
7.4 Device Functional Modes
The OPA4277-SP has a single functional mode and is operational when the power-supply voltage, (V+) – (V–), is
less than 36 V.
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