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 7-1. Maximum Continuous Shunt Current vs Ambient Temperature

Even though the shunt can withstand currents greater than 75 A, the current measurement capability is limited

by ADC full scale range of 78.64 A. The ADC full scale range is also a function of temperature (see Figure 8-1).

In applications with overcurrent transients, the peak amplitude and duration of the overcurrent event is important

to determine the device heating. Figure 7-2 shows the peak pulse current versus pulse duration that the device

can withstand before the maximum junction temperature of 165°C is exceeded. The data shown in this curve

was collected at TA = 25°C, using the INA781 evaluation module (SENS119E0).

Pulse Duration (s)

0.2

1

10

100

1000

80

100

120

140

160

180

200

Figure 7-2. Maximum Pulse Current vs Pulse Duration (Single Event)

7.3.3 Versatile High Voltage Measurement Capability

The INA781 operates off a 2.7 V to 5.5 V supply but can measure voltage and current on rails as high as 85 V.

The current is measured by sensing the voltage drop across an internal shunt resistor. The input stage of the

INA781 is designed such that the input common-mode voltage can be higher than the device supply voltage, VS.

The common-mode voltage range at the inputs is -0.1 V to +85 V to support both high-side and low-side current

measurements. There are no special considerations for power-supply sequencing because the common-mode

input range and device supply voltage are independent of each other; therefore the bus voltage can be present

with the supply voltage off (and vice-versa) without damaging the device.

The device also measures the bus supply voltage through the VBUS pin and temperature through the integrated

temperature sensor. The voltage drop across the internal shunt resistor is measured by the IN+ and IN– pins,

while the bus voltage is measured with respect to device ground. Monitored bus voltages can range from 0 V to

85 V, while monitored temperatures can range from –40°C to +165°C.

Shunt voltage, bus voltage, and internal temperature measurements are multiplexed internally to a single ADC

(see Figure 7-3).

www.ti.com

INA781

SBOSAC0 – JULY 2023

Copyright © 2023 Texas Instruments Incorporated

Submit Document Feedback

9

Product Folder Links: INA781