V

O

R

2

R

1

1

V

O

R

L

1

REF200

100 µA

V+

V

R

INA139

3

4

INA139

3

4

Copyright © 2017, Texas Instruments Incorporated

40

30

20

10

0

–10

–20

100

1k

10k

100k

1M

10M

Frequency (Hz)

R

L = 10 kΩ

R

L = 100 kΩ

R

L = 1 kΩ

15

INA139, INA169

www.ti.com

SBOS181F – DECEMBER 2000 – REVISED FEBRUARY 2017

Product Folder Links: INA139 INA169

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Copyright © 2000–2017, Texas Instruments Incorporated

Typical Applications (continued)

8.2.2.3 Application Curve

Figure 13. Gain vs Frequency

8.2.3 Offsetting the Output Voltage

For many applications using only a single power supply, it may be required to level shift the output voltage away

from ground when there is no load current flowing in the shunt resistor. Level shifting the output of the INA139 or

INA169 devices is easily accomplished by one of two simple methods shown in Figure 14. The method on the

left hand side of Figure 14 illustrates a simple voltage divider method. This method is useful for applications that

require the output of the INA139 or INA169 devices to remain centered with respect to the power supply at zero

load current through the shunt resistor. Using this method the gain is determined by the parallel combination of

R1 and R2, while the output offset is determined by the voltage divider ratio R1 and R2. For applications that may

require a fixed value of output offset independent of the power supply voltage, TI recommends using the current

source method shown on the right hand side of Figure 14 . With this method, a REF200 constant current source

is used to generate a constant output offset. Using this method. the gain is determined by RL and the offset is

determined by the product of the value of the current source and RL.

(1)

Gain set by R1 || R2. Output offset = (VR) R2 / (R1 + R2) using resistor divider.

(2)

Gain set by RL. Output offset = 100 µA × RL (independent of V+) using current source.

Figure 14. Offsetting the Output Voltage