Differential Input Voltage (V)

0

0.2

0.4

0.6

0.8

1

-100

-50

0

50

100

150

200

250

IB+

IB-

Figure 9-2. Input Bias Current vs Differential Input Voltage

Use Equation 1 to calculate the measurement error expected from the additional external filter resistors.

Gain Error (%) = 100

(100

Gain Error Factor)

-

´

(1)

where

• Equation 2 determines the Gain Error Factor

S

3000

Gain Error Factor

R

3000

(2)

Where:

• RS is the external filter resistance value

Use Equation 2 to calculate the gain error factor and determine the gain error introduced by the additional

external series resistance. Use Equation 1 to calculate the deviation of the shunt voltage resulting from the

attenuation and imbalance created by the added external filter resistance. Table 9-1 provides the gain error

factor and gain error for several resistor values.

Table 9-1. Gain Error Factor and Gain Error for External Input Resistors

EXTERNAL RESISTANCE (Ω)

GAIN ERROR FACTOR

GAIN ERROR (%)

5

0.998

0.17

10

0.997

0.33

100

0.968

3.23

9.2 Typical Applications

The INA254 offers advantages for multiple applications including the following:

• High common-mode range and excellent CMRR enables direct inline sensing

• Precision low-inductive, low-drift shunt eliminates the need for overtemperature system calibration

• Ultra-low offset and drift eliminates the necessity of calibration

• Wide supply range enables a direct interface with most microprocessors

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INA254

SLOS974A – JUNE 2021 – REVISED MARCH 2023

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