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 commonmode

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.