AD8211

Rev. A | Page 11 of 16

APPLICATION NOTES

OUTPUT LINEARITY

In all current sensing applications, and especially in automotive

and industrial environments where the common-mode voltage

can vary significantly, it is important that the current sensor

maintain the specified output linearity, regardless of the input

differential or common-mode voltage. The AD8211 contains

specific circuitry on the input stage, which ensures that even

when the differential input voltage is very small, and the

common-mode voltage is also low (below the 5 V supply),

the input-to-output linearity is maintained. Figure 24 shows

the input differential voltage vs. the corresponding output

voltage at different common modes.

200

0

0

DIFFERENTIAL INPUT VOLTAGE (mV)

10

180

160

140

120

100

80

60

40

20

1

2

3

4

5

6

7

8

9

Figure 24. Gain Linearity Due to Differential and Common-Mode Voltage

Regardless of the common mode, the AD8211 provides a

correct output voltage when the input differential is at least

2 mV, which is due to the voltage range of the output amplifier

that can go as low as 33 mV typical. The specified minimum

output amplifier voltage is 100 mV to provide sufficient guard-

bands. The ability of the AD8211 to work with very small

differential inputs, regardless of the common-mode voltage,

allows for more dynamic range, accuracy, and flexibility in any

current sensing application.