Datasheet

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Data Sheet AD8210

Rev. D | Page 13 of 16

INPUT FILTERING

In typical applications, such as motor and solenoid current

sensing, filtering at the input of the AD8210 can be beneficial

in reducing differential noise, as well as transients and current

ripples flowing through the input shunt resistor. An input low-

pass filter can be implemented as shown in Figure 32.

The 3 dB frequency for this filter can be calculated by

FILTER

×××

2π

dB3_

(1)

Adding outside components, such as R

FILTER

and C

FILTER

introduces additional errors to the system. To minimize these

errors as much as possible, it is recommended that R

FILTER

10 Ω or lower. By adding the R

FILTER

in series with the 2 kΩ

internal input resistors of the AD8210, a gain error is

introduced. This can be calculated by













−

×−=

FILTER

ErrorGain

kΩ2

100100(%)

(2)

AD8210

OUTPUT

G = +20

SHUNT

< R

FILTER

≤ 10Ω R

FILTER

≤ 10Ω

+IN –IN

REF

GND

REF

05147-013

0.1µF

0V ≤ V

REF

≤ V

Figure 32. Input Low-Pass Filtering