Gain Error (%) = 100

(100

Gain Error Factor)

-

´

F

2500

(3 R )

2500

u

F

1000

R

1000

F

10000

(9 R ) 10000

u

F

25000

(21 R )

25000

u

20

INA180, INA2180

SBOS741A – APRIL 2017 – REVISED AUGUST 2017

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Application Information (continued)

With the adjustment factor from Equation 4, including the device internal input resistance, this factor varies with

each gain version, as shown in Table 1. Each individual device gain error factor is shown in Table 2.

Table 1. Input Resistance

PRODUCT

GAIN

INAx180A1

20

25

INAx180A2

50

10

INAx180A3

100

5

INAx180A4

200

2.5

Table 2. Device Gain Error Factor

PRODUCT

SIMPLIFIED GAIN ERROR FACTOR

INAx180A1

INAx180A2

INAx180A3

INAx180A4

The gain error that can be expected from the addition of the external series resistors can then be calculated

based on Equation 5:

(5)

For example, using an INA180A2 and the corresponding gain error equation from Table 2, a series resistance of

10 Ω results in a gain error factor of 0.991. The corresponding gain error is then calculated using Equation 5,

resulting in an additional gain error of approximately 0.89% solely because of the external 10-Ω series resistors.