AD8216

Rev. 0 | Page 11 of 16

OUTPUT OFFSET ADJUSTMENT

The output of the AD8216 can be adjusted for unidirectional or

bidirectional operation.

UNIDIRECTIONAL OPERATION

Unidirectional operation allows the AD8216 to measure currents

through a resistive shunt in one direction. The basic modes for

unidirectional operation are ground referenced output mode

and V+ referenced output mode.

For unidirectional operation, the output can be set at the

negative rail (near ground) or at the positive rail (near V+)

when the differential input is 0 V. The output moves to the

opposite rail when a correct polarity differential input voltage is

applied. In this case, full scale is approximately 1.6 V. The required

polarity of the differential input depends on the output voltage

setting. If the output is set at the positive rail, the input polarity

needs to be negative to move the output down. If the output is

set at ground, the polarity is positive to move the output up.

GROUND REFERENCED OUTPUT

When using the AD8216 in this mode, both referenced inputs are

tied to ground, which causes the output to sit at the negative rail

when there are zero differential volts at the input (see Figure 24).

AD8216

+IN

–IN

NC

NC = NO CONNECT

GND

V+

OUT

Figure 24. Ground Referenced Output

Table 4. V+ = 5 V

0 V

0.06 V

1.6 V

4.8 V

V+ REFERENCED OUTPUT

The V+ referenced output mode is set when both reference

pins are tied to the positive supply. It is typically used when the

diagnostic scheme requires detection of the amplifier and the

wiring before power is applied to the load (see Figure 25).

AD8216

+IN

–IN

NC

NC = NO CONNECT

GND

V+

OUT

Figure 25. V+ Referenced Output

Table 5. V+ = 5 V

0 V

4.9 V

−1.6 V

0.1 V

BIDIRECTIONAL OPERATION

Bidirectional operation allows the AD8216 to measure currents

through a resistive shunt in two directions.

In this case, the output is set anywhere within the output range.

Typically, it is set at half scale for equal range in both directions.

In some cases, however, it is set at a voltage other than half scale

when the bidirectional current is nonsymmetrical.

+800 mV

4.9 V

−800 mV

0.1V

Adjusting the output is accomplished by applying voltage(s) to

the referenced inputs.

internal offset node. There is no operational difference between

the pins.