8.2.2.5 Input Protection

The inputs are protected with internal diodes connected to the power-supply rails. These diodes clamp the

applied signal to prevent the signal from exceeding the power supplies by more than approximately 0.7 V. If the

signal-source voltage can exceed the power supplies, the source current should be limited to less than 10 mA.

This limiting can generally be done with a series resistor. Some signal sources are inherently current-limited, and

do not require limiting resistors.

8.2.2.6 Channel Crosstalk—Dual Version

The two channels of the INA2126 are completely independent, including all bias circuitry. At dc and low

frequency, there is virtually no signal coupling between channels. Crosstalk increases with frequency and

depends on circuit gain, source impedance, and signal characteristics.

As source impedance increases, careful circuit layout can help achieve lowest channel crosstalk. Most crosstalk

is produced by capacitive coupling of signals from one channel to the input section of the other channel. To

minimize coupling, separate the input traces as far as practical from any signals associated with the opposite

channel. A grounded guard trace surrounding the inputs helps reduce stray coupling between channels.

Carefully balance the stray capacitance of each input to ground, and run the differential inputs of each channel

parallel to each other, or directly adjacent on top and bottom side of a circuit board. Stray coupling then tends to

produce a common-mode signal that is rejected by the IA input.

8.2.3 Application Curves

Differential signal is too small to be seen

Figure 8-4. Common-mode Signal at INA126 Input

space

Figure 8-5. FFT of Signal in Previous Figure Shows

Both the 60-Hz Common-mode Along With 5-kHz

Differential Signal

Figure 8-6. Recovered Differential Signal at the

Output of the INA126 With a Gain of 250

Figure 8-7. FFT of the INA126 Output Shows that

the 60-Hz Common-mode Signal is Rejected

INA126, INA2126

SBOS062C – SEPTEMBER 2000 – REVISED JANUARY 2022

www.ti.com

16

Submit Document Feedback

Copyright © 2022 Texas Instruments Incorporated

Product Folder Links: INA126 INA2126