The measurement error expected from the additional external filter resistors can be calculated using Equation 4,

where the gain error factor is calculated using Equation 5.

Gain Error (%) = 100

(100

Gain Error Factor)

-

´

(4)

The gain error factor, shown in Equation 4, can be calculated to determine the gain error introduced by the

additional external series resistance. Equation 4 calculates the deviation of the shunt voltage, resulting from the

attenuation and imbalance created by the added external filter resistance. Table 8-2 provides the gain error

factor and gain error for several resistor values.

Gain Error Factor =

(5)

Where:

Table 8-2. Example Gain Error Factor and Gain Error for 10-Ω External Filter Input Resistors

DEVICE (GAIN)

GAIN ERROR FACTOR

GAIN ERROR (%)

INA293-Q1x1 (20)

0.997108386

-0.289161432

INA293-Q1x2 (50)

0.996512207

-0.348779273

INA293-Q1x3 (100)

0.996512207

-0.348779273

INA293-Q1x4 (200)

0.995520159

-0.447984072

INA293-Q1x5 (500)

0.992555831

-0.744416873

8.2 Typical Application

The INA293-Q1 is a unidirectional, current-sense amplifier capable of measuring currents through a resistive

shunt with shunt common-mode voltages from –4 V to +110 V.

GND

MCU

24 V

Solenoid

5 V

INA

R

SENSE

I

SENSE

ADC

Figure 8-2. Current Sensing in a Solenoid Application

8.2.1 Design Requirements

In this example application, the common-mode voltage ranges from 0 V to 24 V. The maximum sense current is

1.5 A, and a 5-V supply is available for the INA293-Q1. Following the design guidelines from Section 8.1.1, a

design setup for this application.

Table 8-3. Design Parameters

DESIGN PARAMETERS

EXAMPLE VALUE

Power supply voltage

5 V

Common mode voltage range

0 V to 24 V

INA293-Q1

SBOS870A – MAY 2019 – REVISED SEPTEMBER 2020

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