G = 1

20mV/div

G = 10

5 s/div

m

G = 10 0

20mV/div

G = 10 0 0

20 s/div

m

47kΩ

47kΩ

10kΩ

Microphone,

Hydrophone

etc.

Thermocouple

Center−tap provides

bias current return.

INA128

INA128

INA128

INA128, INA129

www.ti.com

SBOS051C – OCTOBER 1995 – REVISED OCTOBER 2015

Typical Application (continued)

If the differential source resistance is low, the bias current return path can be connected to one input (see the

thermocouple example in Figure 26). With higher source impedance, using two equal resistors provides a

balanced input, with possible advantages of lower input offset voltage due to bias current and better high-

frequency common-mode rejection.

Figure 26. Providing an Input Common-Mode Current Path

8.2.3 Application Curves

G = 100, 1000

G = 1, 10

Figure 28. Small Signal

Figure 27. Small Signal

Copyright © 1995–2015, Texas Instruments Incorporated

Submit Documentation Feedback

15

Product Folder Links: INA128 INA129