7.3.2 Low Input Bias Current

The topology in the INA151 build in an input bias current stage that requires a typical common-mode bias current

of 20μA to allow operate at very high common-mode voltages. As shown in Figure 7-4, the bias stage allows the

common-mode bias current to be constant across the common-mode range, enabling minimal error implications

for a precision voltage monitoring system.

The bias circuit in the INA151 includes resistance between the input pins with an effective differential input

impedance of 45kΩ. This differential impedance creates differential input bias current flowing in and out of the

device proportional to the input differential voltage, depicted in Figure 7-5. The total input bias current for each

input pin is the summation of the common-mode leakage from input to reference, IBCM, and the differential

current, IBDIFF.

Common-Mode Voltage (V)

-10

0

10

20

30

40

50

60

70

80

90 100 110

-24.5

-24

-23.5

-23

-22.5

-22

-21.5

-21

-20.5

-20

G = 1

G = 2/3

G = 1/2

G = 1/4

Figure 7-4. INA151 Input Bias Current vs Common-Mode Voltage

Differential Input Voltage (V)

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

-60

-40

-20

0

20

40

IB+

IB-

Figure 7-5. INA151 Input Bias Current vs Differential Input Voltage

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INA151

SLVSIL6C – JANUARY 2026 – REVISED APRIL 2026

Copyright © 2026 Texas Instruments Incorporated

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