7.3.1.4 Wide Supply Range

The INA280 operates with a wide supply range from a 2.7 V to 20 V. The output stage supports a full-scale

output voltage range of up to VS. Wide output range can enable very-wide dynamic range current

measurements. For a gain of 20 V/V, the maximum differential input acceptable is 1 V.

7.4 Device Functional Modes

7.4.1 Unidirectional Operation

The INA280 measures the differential voltage developed by current flowing through a resistor that is commonly

referred to as a current-sensing resistor or a current-shunt resistor. The INA280 operates in unidirectional mode

only, meaning it only senses current sourced from a power supply to a system load as shown in Figure 7-3.

+

±

Buffer

Current

Feedback

RL

R1

R1

Bias

48-V

Supply

Load

IN+

IN±

5 V

RSENSE

OUT

GND

ISENSE

Figure 7-3. Unidirectional Application

The linear range of the output stage is limited to how close the output voltage can approach ground under zero-

input conditions. The zero current output voltage of the INA280 is very small, with a maximum of GND + 25 mV.

Make sure to apply a sense voltage of (25 mV / Gain) or greater to keep the INA280 output in the linear region of

operation.

7.4.2 High Signal Throughput

With a bandwidth of 1.1 MHz at a gain of 20 V/V and a slew rate of 2 V/µs, the INA280 is specifically designed

for detecting and protecting applications from fast inrush currents. As shown in Table 7-2, the INA280 responds

in less than 2 µs for a system measuring a 75-A threshold on a 2-mΩ shunt.

Table 7-2. Response Time

PARAMETER

EQUATION

INA280

AT VS = 5 V

G

Gain

20 V/V

IMAX

Maximum current

100 A

IThreshold

Threshold current

75 A

RSENSE

Current sense resistor value

2 mΩ

VOUT_MAX

Output voltage at maximum current

VOUT = IMAX × RSENSE × G

4 V

VOUT_THR

Output voltage at threshold current

VOUT_THR = ITHR × RSENSE × G

3 V

SR

Slew rate

2 V/µs

Output response time

Tresponse = VOUT_THR / SR

< 2 µs

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INA280

SBOSA19 – OCTOBER 2020

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