The negative swing specification limits how small the sense resistor value can be for a given application.

Equation 3 provides the limit on the minimum value of the sense resistor.

I

MIN

ª RSENSE ª *$,1 > VSN

(3)

where:

• IMIN is the minimum current that will flow through RSENSE.

• GAIN is the gain of the current-sense amplifier.

• VSN is the negative output swing of the device.

9.2 Typical Application

Figure 9-1 shows the basic connections for the INA183. The input pins, IN+ and IN–, must be connected as

close as possible to the shunt resistor to minimize any resistance in series with the shunt resistor.

Server 12-V

Subsystem

IN+

IN-

RSENSE

GND

OUT

12V Server

Power

Supply

INA183

0.1 …F

CBYP

Figure 9-1. Typical Server Application

A power-supply bypass capacitor is required on the IN+ pin. Applications with noisy or high-impedance power

supplies may require additional decoupling capacitors to reject power-supply noise. Connect bypass capacitors

close to the device pins.

In server applications, the INA183 typically monitors the current on the 12-V bus that is distributed to various

server sub-systems like memory, storage, or CPU power. The monitored current can be used by the server for

fault detection or sub-system power optimization.

9.2.1 Design Requirements

Table 9-1 lists the design setup for this application.

Table 9-1. Design Parameters

DESIGN PARAMETERS

EXAMPLE VALUE

High-side supply voltage (VIN+)

12 V

Maximum sense current (IMAX)

5 A

Gain option

50 V/V

9.2.2 Detailed Design Procedure

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

maximum current the be sensed (IMAX), and the power-supply voltage (VIN+). When operating at the maximum

current, the output voltage must not exceed the positive output swing specification, VSP. Under the given design

parameters, Equation 4 calculates the maximum value for RSENSE as 47.2 mΩ.

SP

SENSE

MAX

V

R

<

I

GAIN

u

(4)

www.ti.com

INA183

SBOSA08 – FEBRUARY 2021

Copyright © 2021 Texas Instruments Incorporated

Submit Document Feedback

13

Product Folder Links: INA183