´

Power Register

Current Register

I C

2

Interface

Voltage Register

GND

BUS

ADC

V

I

A0

ALERT

A1

SDA

SCL

C

0.1 F

BYPASS

m

Load

Alert Register

V

(Supply Voltage)

S

Power Supply

(0 V to 28 V)

R

10

FILTER

W

£

R

10

FILTER

W

£

C

0.1 F to 1 F

Ceramic

Capacitor

FILTER

m

m

IN-

IN+

29

INA231

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SBOS644B – FEBRUARY 2013 – REVISED AUGUST 2017

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Copyright © 2013–2017, Texas Instruments Incorporated

Application Information (continued)

Figure 28. INA231 With Input Filtering

Overload conditions are another consideration for the INA231 inputs. The INA231 inputs are specified to tolerate

30 V across the inputs. A large differential scenario might be a short to ground on the load side of the shunt. This

type of event can result in full power-supply voltage across the shunt (as long as the power supply or energy

storage capacitors support it). Keep in mind that removing a short to ground can result in inductive kickbacks that

could exceed the 30-V differential and common-mode rating of the INA231. Inductive kickback voltages are best

controlled by zener-type transient-absorbing devices (commonly called transzorbs) combined with sufficient

energy storage capacitance.

In applications that do not have large energy-storage electrolytics on one or both sides of the shunt, an input

overstress condition may result from an excessive dV/dt of the voltage applied to the input. A hard physical short

is the most likely cause of this event, particularly in applications with no large electrolytics present. This problem

occurs because an excessive dV/dt can activate the ESD protection in the INA231 in systems where large

currents are available. Testing has demonstrated that the addition of 10-Ω resistors in series with each input of

the INA231 sufficiently protect the inputs against this dV/dt failure up to the 30-V rating of the INA231. Selecting

these resistors in the range noted has minimal effect on accuracy.