I

S

R

S

V

IN+

Up To 60 V

3

4

V

IN+

V

IN–

5 k

5 k

Load

V+

5

GND

2

OUT

1

V = I R R

O

S

S

L / 5 k

Copyright © 1999, Texas Instruments Incorporated

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Design

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.

INA138, INA168

SBOS122E – DECEMBER 1999 – REVISED DECEMBER 2017

INA1x8 High-Side Measurement Current Shunt Monitor

1

1 Features

1

•

Complete Unipolar High-Side Current

Measurement Circuit

•

Wide Supply and Common-Mode Range

•

INA138: 2.7 V to 36 V

•

INA168: 2.7 V to 60 V

•

Independent Supply and Input Common-Mode

Voltages

•

Single Resistor Gain Set

•

Low Quiescent Current (25 µA Typical)

•

Wide Temperature Range: –40°C to +125°C

•

5-Pin SOT-23 Package

2 Applications

•

Current Shunt Measurement:

–

Telephone, Computers

•

Portable and Battery-Backup Systems

•

Battery Chargers

•

Power Management

•

Cell Phones

•

Precision Current Source

3 Description

The INA138 and INA168 (INA1x8) are high-side,

unipolar, current shunt monitors. Wide input common-

mode voltage range, low quiescent current, and tiny

SOT-23 packaging enable use in a variety of

applications.

Input common-mode and power-supply voltages are

independent and can range from 2.7 V to 36 V for the

INA138 and 2.7 V to 60 V for the INA168. Quiescent

current is only 25 µA, which permits connecting the

power

supply

to

either

side

of

the

current

measurement shunt with minimal error.

The device converts a differential input voltage to a

current output. This current is converted back to a

voltage with an external load resistor that sets any

gain from 1 to over 100. Although designed for

current

shunt

measurement,

the

circuit

invites

creative applications in measurement and level

shifting.

Both the INA138 and INA168 are available in SOT23-

5 and are specified for the –40°C to 125°C

temperature range.

Device Information(1)

PART NUMBER

PACKAGE

BODY SIZE (NOM)

INA138

SOT-23 (5)

2.90 mm × 1.60 mm

INA168

(1) For all available packages, see the package option addendum

at the end of the datasheet.

Typical Application Circuit