G = 1

20mV/div

G = 10

5 s/div

m

G = 10 0

20mV/div

G = 10 0 0

20 s/div

m

47kW

47kW

10kW

Microphone,

Hydrophone

etc.

Thermocouple

Center-tap provides

bias current return.

INA129

INA129

INA129

INA129-EP

www.ti.com

SBOS508A – DECEMBER 2009 – REVISED DECEMBER 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 18). 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 18. Providing an Input Common-Mode Current Path

8.2.3 Application Curves

G = 100, 1000

G = 1, 10

Figure 20. Small Signal

Figure 19. Small Signal

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