Bus Supply

±0.2 V to +26 V

High-Side Sensing

Low-Side Sensing

LOAD

is bus-voltage dependent.

is always near ground and is

isolated from bus-voltage spikes.

Direction of Positive

Current Flow

IN+

Direction of Positive

Current Flow

IN±

IN+

IN±

14

INA180, INA2180

SBOS741A – APRIL 2017 – REVISED AUGUST 2017

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8.3 Feature Description

8.3.1 High Bandwidth and Slew Rate

The INAx180 support small-signal bandwidths as high as 350 kHz, and large-signal slew rates of 2 V/µs. The

ability to detect rapid changes in the sensed current, as well as the ability to quickly slew the output, make the

INAx180 a good choice for applications that require a quick response to input current changes. One application

that requires high bandwidth and slew rate is low-side motor control, where the ability to follow rapid changing

current in the motor allows for more accurate control over a wider operating range. Another application that

requires higher bandwidth and slew rates is system fault detection, where the INAx180 are used with an external

comparator and a reference to quickly detect when the sensed current is out of range.

8.3.2 Wide Input Common-Mode Voltage Range

The INAx180 support input common-mode voltages from –0.2 V to +26 V. Because of the internal topology, the

INAx180 to be used in high-side, as well as low-side, current-sensing applications, as shown in Figure 36.

Figure 36. High-Side and Low-Side Sensing Connections

8.3.3 Precise Low-Side Current Sensing

When used in low-side current sensing applications the offset voltage of the INAx180 is less than 150 µV. The

low offset performance of the INAx180 has several benefits. First, the low offset allows the device to be used in

applications that must measure current over a wide dynamic range. In this case, the low offset improves the

accuracy when the sensed currents are on the low end of the measurement range. Another advantage of low

offset is the ability to sense lower voltage drop across the sense resistor accurately, thus allowing a lower-value

shunt resistor. Lower-value shunt resistors reduce power loss in the current sense circuit, and help improve the

power efficiency of the end application.

The gain error of the INAx180 is specified to be within 1% of the actual value. As the sensed voltage becomes

much larger than the offset voltage, this voltage becomes the dominant source of error in the current sense

measurement.