Data Sheet

AD8215

Rev. B | Page 11 of 13

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 AD8215 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 27 shows the

differential input 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

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Figure 27. Gain Linearity due to Differential and Common-Mode Voltage

Regardless of the common mode, the AD8215 provides a

correct output voltage when the differential input 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 AD8215 to work with very small

differential inputs, regardless of the common-mode voltage,

allows more dynamic range, accuracy, and flexibility in any

current sensing application.