OUTMIN

MIN

SENSE

V

I

R

GAIN

u

u

SP

SENSE

MAX

V

R

<

I

GAIN

u

ENABLE

VS

OUT

REF

GND

IN+

IN±

LOAD

0.1 F

5 V

12 V

INA190

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13

INA190

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SBOS863 – MARCH 2018

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Copyright © 2018, Texas Instruments Incorporated

8.2 Typical Applications

8.2.1 Microamp Current Measurement

The low input bias current of the INA190 allows accurate monitoring of small-value currents. To accurately

monitor currents on the microamp range, increase the value of the sense resistor to increase the sense voltage,

so that the error introduced by the offset voltage is small. The circuit configuration for monitoring low-value

currents is shown in Figure 5. As a result of the differential input impedance of the INA190, limit the value of

Figure 5. Measuring Microamp Currents

8.2.1.1 Design Requirements

The design requirements for the circuit shown in Figure 5, are listed in Table 1

Table 1. Design Parameters

DESIGN PARAMETER

EXAMPLE VALUE

5 V

12 V

1 µA

150 µA

Device gain (GAIN)

25 V/V

0 V

8.2.1.2 Detailed Design Procedure

The maximum value of the current-sense resistor is calculated based choice of gain, value of the maximum

(5)

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