INA216 datasheet(9/19 Pages) TI

9 / 19 page

OUT

IN-

IN+

GND

SHUNT

INA216

Load

OUT

IN-

IN+

GND

SHUNT

INA216

Load

= 1.8 V

to 5.5V

OUT

IN-

IN+

GND

SHUNT

INA216

Load

INA216

www.ti.com

SBOS503B – JUNE 2010 – REVISED JUNE 2010

APPLICATION INFORMATION

Basic Connections

Figure 18 shows the basic connections of the

INA216. The input pins, IN+ and IN–, should be

connected as closely as possible to the shunt resistor

to minimize any resistance in series with the shunt

resistance.

Figure 20. Shunt Resistance Measurement Using

a Kelvin Connection

Power Supply

The INA216 does not have a dedicated power-supply

pin. Instead, an internal connection to the IN+ pin

serves as the power supply for this device. Because

Figure 18. Typical Application

the INA216 is powered from the IN+ pin, the

common-mode input range is limited on the low end

Figure 19 illustrates the INA216 connected to a shunt

to 1.8V. Therefore, the INA216 cannot be used as a

resistor with additional trace resistance in series with

low-side current shunt monitor.

the shunt placed between where the current shunt

monitors the input pins. With the typically low shunt

Selecting RS

resistor values commonly used in these applications,

even small amounts of additional impedance in series

The selection of the value of the shunt resistor (RS) to

with the shunt resistor can significantly affect the

use with the INA216 is based on the specific

differential voltage present at the INA216 input pins.

operating

conditions

and

requirements

the

application. The starting point for selecting the

resistor is to first determine the desired full-scale

output from the INA216. The INA216 is available in

four gain options: 25, 50, 100, and 200. By dividing

the desired full-scale output by each of the gain

options, there are then four available differential input

voltages that can achieve the desired full-scale output

voltage, given that the appropriate gain device is

used. With four values for the total voltage that is to

be dropped across the shunt, the decision on how

much of a drop is allowed in the application must be

made. Most applications have a maximum drop

allowed to ensure that the load receives the required

voltage necessary to operate. Assuming that there

Figure 19. Shunt Resistance Measurement

are now multiple shunt voltages that are acceptable

Including Trace Resistance, RP

(based on the design criteria), the choice of what

value shunt resistor to use can be made based on

Figure 20 shows a proper Kelvin, or four-wire,

accuracy. As a result of the INA216 auto-zero

connection of the shunt resistor to the INA216 input

architecture, the input offset voltage is extremely low.

pins. This connection helps ensure that the only

However, even the 100mV maximum input offset

impedance between the current monitor input pins is

voltage specification plays a role in the decision of

the shunt resistor.

which shunt resistor value to choose. With a larger

shunt voltage present at the current shunt monitor

input, less error is introduced by the input offset

voltage.

Submit Documentation Feedback

Product Folder Link(s): INA216

INA216 Scheda tecnica(PDF) 9 Page - Texas Instruments

INA216 Scheda tecnica(HTML) 9 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Scheda tecnica Scarica

Link URL