9 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification,

and TI does not warrant its accuracy or completeness. TI’s customers are responsible for

determining suitability of components for their purposes, as well as validating and testing their design

implementation to confirm system functionality.

9.1 Application Information

The INA241x amplifies the voltage developed across a current-sensing resistor as current flows through

the resistor to the load. The wide input common-mode voltage range and high common-mode rejection of

the INA241x make it usable over a wide range of voltage rails while still maintaining an accurate current

measurement.

The accuracy of any current-sense amplifier is maximized by choosing the largest current-sense resistor value

possible. A larger value sense resistor maximizes the differential input signal for a given amount of current

flow and reduces the error contribution of the offset voltage. However, there are practical limits as to how

large the current-sense resistor value can be in a given application because of the physical dimensions of the

package, package construction, and maximum power dissipation. Equation 1 gives the maximum value for the

current-sense resistor for a given power dissipation budget:

MAX

SENSE

2

MAX

PD

R

I

(1)

where:

An additional limitation on the size of the current-sense resistor and device gain is due to the power-supply

to the output, both positive and negative output swing limitations must be examined. Equation 2 provides the

I

MAX

(2)

where:

• GAIN is the gain of the current-sense amplifier.

between the value of the sense resistor and the gain of the device under consideration. If the sense resistor

selected for the maximum power dissipation is too large, then it is possible to select a lower-gain device to avoid

positive swing limitations.

The negative swing limitation places a limit on how small the sense resistor value can be for a given application.

Equation 3 provides the limit on the minimum value of the sense resistor.

I

MIN

(3)

where:

INA241A, INA241B

SBOSA30 – MARCH 2022

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Product Folder Links: INA241A INA241B