INA138NASLASH3K datasheet(8/27 Pages) TI1

8 / 27 page

VIN+

VIN-

V+

OUT

GND

INA138, INA168

SBOS122D – DECEMBER 1999 – REVISED DECEMBER 2014

www.ti.com

7 Detailed Description

7.1 Overview

The INA138 and INA168 devices are comprised of a high voltage, precision operational amplifier, precision thin

film resistors trimmed in production to an absolute tolerance and a low noise output transistor. The INA138 and

INA168 devices can be powered from a single power supply and their input voltages can exceed the power

supply voltage. The INA138 and INA168 devices are ideal for measuring small differential voltages, such as

those generated across a shunt resistor, in the presence of large common-mode voltages. Refer to Functional

Block Diagram which illustrates the functional components within both INA138 and INA168 devices.

7.2 Functional Block Diagram

7.3 Feature Description

7.3.1 Output Voltage Range

The output of the INA138 device is a current, which is converted to a voltage by the load resistor, RL. The output

current remains accurate within the compliance voltage range of the output circuitry. The shunt voltage and the

input common-mode and power-supply voltages limit the maximum possible output swing. The maximum output

voltage compliance is limited by the lower of the following two equations:

Vout max = (V+) – 0.7 V – (VIN+ – VIN–)

(1)

Vout max = VIN– – 0.5 V

(2)

(whichever is lower)

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INA138NA/3K Datasheet(PDF) 8 Page - Texas Instruments