VS

GND

OUT

ALERT

IN+

IN-

LIMIT

Load

Power Supply

(0 V to 36 V)

2.7 V to 5.5 V

RPULL-UP

10k

RSET

Gain = 20, 50,

100

RESET

+

+

INA301

CBYPASS

0.1 PF

13

INA301

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SBOS713A – SEPTEMBER 2015 – REVISED FEBRUARY 2016

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7 Detailed Description

7.1 Overview

The INA301 is a 36-V common-mode, zero-drift topology, current-sensing amplifier that can be used in both low-

side and high-side configurations. These specially-designed, current-sensing amplifiers are able to accurately

measure voltages developed across current-sensing resistors (also known as current-shunt resistors) on

common-mode voltages that far exceed the supply voltage powering the device. Current can be measured on

input voltage rails as high as 36 V, and the device can be powered from supply voltages as low as 2.7 V. The

device can also withstand the full 36-V common-mode voltage at the input pins when the supply voltage is

removed without causing damage.

The zero-drift topology enables high-precision measurements with maximum input offset voltages as low as

35

μV with a temperature contribution of only 0.5 μV/°C over the full temperature range of –40°C to +125°C. The

low total offset voltage of the INA301 enables smaller current-sense resistor values to be used, and allows for a

more efficient system operation without sacrificing measurement accuracy resulting from the smaller input signal.

The INA301 uses a single external resistor to allow for a simple method of setting the corresponding current

threshold level for the device to use for out-of-range comparison. Combining the precision measurement of the

current-sense amplifier and the on-board comparator enables an all-in-one overcurrent detection device. This

combination creates a highly-accurate solution that is capable of fast detection of out-of-range conditions and

allows the system to take corrective actions to prevent potential component or system-wide damage.

7.2 Functional Block Diagram