-20

-15

-10

-5

0

5

10

15

20

±10

±8

±6

±4

±2

0

2

4

6

8

10

±40

±30

±20

±10

0

10

20

30

40

Input Voltage (V)

Input Current

Output Voltage

C015

+VS

-VS

Overvoltage

Protection

IN

Input Transistor

+V

-V

+

±

Input Voltage

Source

ZD1

ZD2

20

INA828

SBOS792A – AUGUST 2017 – REVISED JANUARY 2018

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Product Folder Links: INA828

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Copyright © 2017–2018, Texas Instruments Incorporated

7.3.4 Input Protection

The inputs of the INA828 device are individually protected for voltages up to ±40 V. For example, a condition of

–40 V on one input and 40 V on the other input does not cause damage. Internal circuitry on each input provides

low series impedance under normal signal conditions. If the input is overloaded, the protection circuitry limits the

input current to a value of approximately 8 mA.

Figure 59. Input Current Path During an Overvoltage Condition

During an input overvoltage condition, current flows through the input protection diodes into the power supplies,

see Figure 59. If the power supplies are unable to sink current, then Zener diode clamps (ZD1 and ZD2 in

Figure 59) must be placed on the power supplies to provide a current pathway to ground. Figure 60 illustrates the

input current for input voltages from –40 V to +40 V when the INA828 is powered by ±15-V supplies.

Figure 60. Input Current vs Input Overvoltage