8 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. Customers should validate and test their design

implementation to confirm system functionality.

8.1 Application Information

The LM290xLV-Q1 devices are a family of low-power, cost-optimized operational amplifiers. The devices operate

from 2.7 V to 5.5 V, are unity-gain stable, and are suitable for a wide range of general-purpose automotive

applications. The input common-mode voltage range includes the negative rail, and allows the LM290xLV-Q1 to

be used in any single-supply applications.

8.2 Typical Application

Figure 8-1 shows the LM290xLV-Q1 device configured in a low-side current sensing application.

V

BUS

0.1 Ÿ

255 NŸ

7.5 NŸ

5 V

+

í

+

í

Figure 8-1. LM290xLV-Q1 Device in a Low-Side, Current-Sensing Application

8.2.1 Design Requirements

The design requirements for this design are:

• Load current: 0 A to 1 A

• Output voltage: 3.5 V

• Maximum shunt voltage: 100 mV

8.2.2 Detailed Design Procedure

The transfer function of the circuit in Figure 8-1 is given in Equation 1:

OUT

LOAD

SHUNT

V

I

R

Gain

u

u

(1)

0 A to 1 A. To keep the shunt voltage below 100 mV at maximum load current, the largest allowable shunt

resistor is shown using Equation 2:

_

_

SHUNT

MAX

SHUNT

LOAD

MAX

V

100mV

R

100m

I

1A

:

(2)

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LM2902LV-Q1, LM2904LV-Q1

SBOS987 – AUGUST 2020

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