Temperature ( C)

-50

-25

0

25

50

75

100

125

150

400

450

500

550

600

650

700

750

Figure 6-1. IS+ to IS– Package Resistance vs Temperature

6.3.2 Safe Operating Area

The heat dissipated across the package when current flows through the device ultimately determines the

maximum current that can be safely handled by the package. The current consumption of the silicon is relatively

low, leaving the total package resistance to carry the high load current as the primary contributor to the total

power dissipation of the package. The maximum safe-operating current level shown in Figure 6-2 is set to make

sure that the heat dissipated across the package is limited so that no damage occurs to the resistor or the

package, or that the internal junction temperature of the silicon does not exceed a 165°C limit.

External factors, such as ambient temperature, external air flow, and PCB layout, contribute to how effectively

the device dissipates heat. The internal heat is developed as a result of the current flowing through the total

package resistance of 550µΩ.

Ambient Temperature (°C)

-20

0

20

40

60

80

100

120

140

160

180

0

10

20

30

40

50

60

70

80

90

100

110

Figure 6-2. Maximum Continuous Current vs Ambient Temperature

6.3.3 Short-Circuit Duration

The INA790x features a physical shunt resistance that is able to withstand current levels higher than the

continuous handling limit of 50A without sustaining damage to the current-sensing resistor or the current-sensing

amplifier, if the excursions are brief. Figure 6-3 shows the short-circuit duration curve for the INA790x .

INA790A, INA790B

SBOSAA6B – MAY 2024 – REVISED JULY 2025

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