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.