INA745AIRELR datasheet(12/50 Pages) TI2

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6 Detailed Description

6.1 Overview

The INA745x device is a digital current sense amplifier with an integrated current sensing element. The device

measures current, bus voltage and internal temperature while calculating power, energy and charge necessary

for accurate decision making in precisely controlled systems. Programmable registers allow flexible configuration

for measurement precision as well as continuous or triggered operation. Detailed register information is found in

6.2 Functional Block Diagram

GND

16 – bit ADC

Common-mode Voltage

(-0.1V to 40V)

TI Device

IS+

IS-

±0.5% Oscillator

VBUS

IN+

IN-

SH+

SH-



Power

Current

Bus Voltage

Temperature

Energy

Charge

Alert_Diag

Shunt TC

Compensation

Registers

2C / SMBus

Interface

ALERT

SDA

SCL

0.1µF

Supply Voltage

(2.7V to 5.5V)

6.3 Feature Description

6.3.1 Integrated Shunt Resistor

The INA745x is a precise, low-drift, digital power monitor that provides accurate measurements over the entire

specified ambient temperature range of –40°C to 125°C. The integrated current-sensing resistor is internally

compensated to provide measurement stability over temperature, while simplifying printed circuit board (PCB)

layout and size constraints.

Access to the on-chip current-sensing resistor is provided by the IS+ and IS- pins. This resistor features internal

sense connections that are brought out on the SH+ and SH- pins. Access to the digital power monitor is

provided by the IN+ and IN- pins. When the shunt sense connections are connected to the digital power monitor

inputs, the sensed voltage is calibrated and temperature compensated to achieve a high level of accuracy. The

construction of this resistor does not allow the device to be used as a stand-alone component for accurate

current measurement. The INA745x is system-calibrated to verify that the current-sensing resistor and digital

power monitor are both precisely matched to one another.

The nominal pin-to-pin resistance from IS+ to IS- is approximately 1mΩ, while the internal resistance seen by

the SH+ and SH- pins is nominally 800μΩ. The power dissipation requirements of the system and package are

based on the total package resistance between the IS+ and IS– pins.

INA745A, INA745B

SBOSAC3B – JULY 2023 – REVISED AUGUST 2025

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